Maintenance procedure · Written to ASD-STE100 Issue 9 · Formatted to ANSI Z535

Find Where a Water Heater Is Leaking: Six Origins, One of Which Means the Tank Is Finished

Storage water heaters, gas or electric — sort water on the floor into condensation, a connection, the relief valve, the drain valve, the tank itself, or a pipe overhead, before anybody quotes you for a replacement
ApplicabilityStorage water heaters with a tank, gas-fired or electric, installed in a house or an apartment. Not tankless water heaters, and not a boiler that heats the building.
Task time1 hr 14 min to 3 hr 26 min editorial estimate, not a measurement
PersonnelOne
Revisionv2 · 2026-08-12
BEFORE YOU BEGIN

Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.

Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.

Summary

Water on the floor under a water heater is not one fault. It has six common origins and they do not have the same answer. Condensation is not a leak at all, and A. O. Smith's own gas guide says so in as many words: "Condensation is not a leak and will go away once the tank reaches normal operating temperature." A wet pipe connection at the top is the usual finding rather than the unusual one, and the same manufacturer's installation check states that "Almost all leaks occur at connections and are not a tank leak." A drip from the relief valve discharge pipe is mostly a message about the water pressure in the house. Water that comes from the body of the tank is the one result that ends the argument, because Rheem says that pooling water around the tank body "often indicates internal corrosion that has eaten through the metal, and once a tank begins to deteriorate from the inside, replacement becomes the only safe and cost-effective solution."

This page sorts the origin and it repairs nothing. The first instruction is to switch the power off, and that ordering is the point rather than a formality: A. O. Smith's electric guide tells owners to "Disconnect power by opening the circuit breaker or removing the fuses before installing or servicing", and Rheem's own emergency page for a leaking water heater puts the electricity off before the water off.

Standing in water beside a live appliance is the part of this job that can kill you, and it comes before you have learned anything at all. Every result that is a leak then routes to a licensed plumber, because this site does not publish water heater repair. The one result that is not a leak — condensation — routes nowhere at all, and separating it from the other five is half the value of the page. The other half is the single sentence that decides what the visit costs: which part was wet.

Necessary equipment

ItemNote
FlashlightThe space around a water heater has low light.
Dry clothUse the cloth to make each connection and the tank dry.
Paper towelPut the paper towel on the floor. A new drop of water is then easy to see.
Mirror optionalUse the mirror to look at the back of the water heater.
Pen and paperWrite the result before you speak to a plumber.
Camera optionalMake a photograph of the wet part.

Make the water heater safe

Estimated 5 min to 12 min

NOTEDo this section before you touch the water heater.
Quantity of water on the floor that makes this an emergency
Unverified — do not rely on this value
CONSULT A LICENSED PLUMBER. A FLOW THAT DOES NOT STOP IS ALWAYS AN EMERGENCY.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

WARNING

SET THE ELECTRICAL POWER TO OFF BEFORE YOU TOUCH THE WATER HEATER OR THE WATER ON THE FLOOR.
A. O. Smith tells owners to disconnect the power before service. An electric shock can kill you.

  1. Set the electrical power to the water heater to off.
    • Use the switch near the water heater, or use the circuit breaker for the water heater.
    • A gas water heater can also have electrical power for its control.
    • Rheem tells owners to set the electricity to off before the water supply.
    2m
  2. If the water heater has a gas control knob, set the knob to off.
    • The gas control knob is near the bottom of a gas water heater.
    • The burner then needs the procedure on the label to start again.
    <1m
WARNING

DO NOT TOUCH THE WATER FROM THE WATER HEATER.
A. O. Smith tells owners that this water can be very hot. Hot water can burn you.

  1. Look at the quantity of water on the floor.
    <1m
  2. If water flows quickly onto the floor, close the cold water valve.
    • The cold water valve is above the water heater.
    • Rheem tells owners to close the valve above the intake of the water heater.
    • Turn the handle of the valve clockwise.
    1m
  3. If water flows quickly onto the floor, speak to a licensed plumber immediately.
    • Do not continue with this page.
    • A large flow of water is not a diagnostic problem. It is an emergency.
    1m

Make the water heater and the floor dry

Estimated 14 min to 29 min

NOTEA dry surface shows a new drop of water.
  1. Make the top of the water heater dry with a cloth.
    2m
  2. Make each pipe connection at the top of the water heater dry.
    • There are two connections at the top. One is for the cold water and one is for the hot water.
    • A. O. Smith gives this same instruction to an installer, because a wet connection is easy to miss on a wet pipe.
    2m
  3. Make the outside of the tank dry with a cloth.
    • Include the seam at the bottom of the tank.
    2m
WARNING

DO NOT PUT YOUR HAND OR YOUR FACE BELOW THE END OF THE DISCHARGE PIPE.
Very hot water can flow from this pipe. Hot water can burn you.

  1. Make the discharge pipe from the relief valve dry.
    • The relief valve is on the top or on the side of the tank.
    • The discharge pipe goes down from the relief valve to a position near the floor.
    1m
  2. Make the drain valve at the bottom of the water heater dry.
    1m
  3. Remove the water from the floor.
    • Include the water in the drain pan below the water heater.
    4m
  4. Put a dry paper towel on the floor below the water heater.
    • Put a paper towel below each connection, below the discharge pipe and below the drain valve.
    2m

Find the origin of the water

Estimated 41 min to 2 hr 17 min

NOTELook at each part in this sequence. Do not stop at the first wet part.
Working water supply pressure A. O. Smith recommends for a house, no higher than
Manufacturer or standard verified
50 to 60 psi

Source: Residential Electric Water Heater Installation Instructions and Use & Care Guide (document 100264218) · tier 1 · accessed 2026-08-12

Maximum incoming water supply pressure A. O. Smith says most codes allow
Manufacturer or standard verified
80 psi

Source: Residential Electric Water Heater Installation Instructions and Use & Care Guide (document 100264218) · tier 1 · accessed 2026-08-12

Pressure rating of the relief valve on this water heater
Unverified — do not rely on this value
CONSULT THE RATING PLATE ON THE WATER HEATER AND THE LABEL ON THE VALVE. THE MANUFACTURER MARKS THIS VALUE.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Temperature of the water in the discharge pipe
Unverified — do not rely on this value
CONSULT THE MANUFACTURER DOCUMENTATION. THE WATER CAN BE HOT ENOUGH TO CAUSE A SEVERE BURN.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

  1. Wait 30 minutes.
    • The electrical power and the gas are off. The water heater makes no new condensation in this time.
    • The water in the tank stays at the pressure of the water supply. A leak continues.
    30m
  2. Look at the paper towel on the floor.
    <1m
  3. If all the paper towel is dry, no water came out in this time.
    • Condensation is a usual cause of a small quantity of water below a gas water heater.
    • A. O. Smith tells owners that condensation is normal, and that it stops when the tank becomes hot.
    <1m
  4. Look at each pipe connection at the top of the water heater.
    • Use the flashlight.
    • Touch each connection with a dry finger.
    2m
  5. If a pipe connection is wet, the water comes from that connection.
    • A. O. Smith states that almost all leaks are at connections and not at the tank.
    • This result does not mean that the water heater is at the end of its life.
    <1m
WARNING

DO NOT MOVE THE LEVER ON THE RELIEF VALVE.
A. O. Smith warns that this water can be extremely hot. Hot water can burn you.

  1. Look at the relief valve and at its discharge pipe.
    • Look at the end of the discharge pipe near the floor.
    1m
  2. If the discharge pipe is wet, the water comes from the relief valve.
    • A. O. Smith gives a high pressure in the water supply as the usual cause of a small drip.
    • A. O. Smith gives debris in the valve as a second cause.
    • A large flow of very hot water from this pipe is a different condition. Speak to a licensed plumber immediately.
    <1m
  3. Look at the drain valve at the bottom of the water heater.
    1m
  4. If the drain valve is wet, the water comes from the drain valve.
    • The drain valve is a part. A plumber can replace it.
    <1m
  5. Look at the outside of the tank below the connections and below the valves.
    • Use the flashlight and the mirror.
    • Look for rust on the outside of the tank.
    2m
  6. If the tank is wet and each connection is dry, the tank has a leak.
    • Rheem states that water around the body of the tank usually shows corrosion in the tank.
    • Rheem states that a replacement is then the only safe result.
    • No repair corrects a hole in the tank.
    <1m
  7. Look at the pipes and at the ceiling above the water heater.
    • Water can come from a pipe above the water heater and fall onto it.
    • A. O. Smith names a leak in a water pipe of the house as a separate cause.
    2m
  8. If a pipe above the water heater is wet, the water comes from that pipe.
    • The water heater is then not the cause.
    <1m

Decide what to do

Estimated 10 min to 20 min

NOTEThis section gives no repair.
Maximum interval between inspections of the relief valve by a qualified person
Manufacturer or standard verified
5 years

Source: Residential Electric Water Heater Installation Instructions and Use & Care Guide (document 100264218) · tier 1 · accessed 2026-08-12

WARNING

DO NOT SET THE GAS CONTROL KNOB TO ON WITHOUT THE INSTRUCTIONS FOR THIS WATER HEATER.
A. O. Smith warns that a fire or an explosion can occur.

NOTICE

DO NOT SET THE ELECTRICAL POWER TO ON IF THE TANK IS NOT FULL OF WATER.
A. O. Smith gives this instruction. Damage to the water heater occurs quickly.

  1. If the floor is dry and the paper towel is dry, set the electrical power to on again.
    • This page does not give the procedure to start a gas burner.
    • Read the label on a gas water heater before you start the burner.
    • Look at the floor again after one day.
    • Look at the floor again after one week.
    2m
  2. If you found a leak, keep the electrical power off.
    <1m
  3. If you found a leak, close the cold water valve.
    • The cold water valve is above the water heater.
    • A closed valve stops the flow of new water into the tank.
    1m
  4. Speak to a licensed plumber.
    • Tell the plumber which part was wet.
    • Tell the plumber the age of the water heater.
    • A leak at the tank usually means a replacement.
    • A leak at a connection or at a valve usually does not mean a replacement.
    7m

Record the facts for the plumber

Estimated 5 min to 7 min

  1. Write the model number and the serial number from the rating plate on paper.
    • A. O. Smith tells owners to write these two numbers before they make the call.
    2m
  2. Write the name of the wet part on paper.
    <1m
  3. Write the date and the time on paper.
    <1m
  4. Make a photograph of the wet part.
    1m

Terminology

This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.

water heater
Also called: hot water heater, hot water tank, water boiler, hot water cylinder, geyser, water heater leaking from bottom, puddle under hot water heater
temperature and pressure relief valve
Also called: T&P valve, TPR valve, pressure relief valve, safety valve, pop off valve, the valve with the little lever on top, water heater dripping from pipe
relief valve discharge pipe
Also called: overflow pipe, drain pipe on the water heater, the pipe that runs down to the floor, the pipe that keeps dripping
drain valve
Also called: spigot at the bottom, hose bib on the water heater, the tap at the bottom of the tank, water heater faucet
condensation
Also called: sweating, my water heater is sweating, water heater sweating not leaking, moisture on the tank
cold water valve
Also called: shutoff valve, inlet valve, the valve on top of the water heater, how to turn off water to hot water heater
drain pan
Also called: drip pan, catch pan, the metal tray under the water heater

When to use a professional

This page gives no repair. A licensed plumber does all repair work on a water heater. Speak to a licensed plumber for each result that is a leak. Do not do work on the water pipes of the water heater.

Set the electrical power to off before you touch the water heater. A. O. Smith tells owners to disconnect the power before service. Keep the power off until the plumber comes. Keep the cold water valve closed until the plumber comes.

Do not put a cap on the relief valve. Do not put a plug in the discharge pipe. Do not operate the water heater if the relief valve does not work. A. O. Smith states that this can cause an explosion.

If a large quantity of very hot water comes from the discharge pipe, close the gas supply valve. Then speak to a licensed plumber immediately. A. O. Smith gives this instruction for a tank that becomes too hot.

This page gives no procedure to start a gas burner again. Read the label on a gas water heater. Speak to a licensed plumber if you cannot find the instructions.

If the tank is the origin of the water, the tank is at the end of its life. Rheem states that a replacement is then the only safe result. Ask the plumber for a written estimate before the work starts.

Common questions

Is a leaking water heater an emergency?

It depends entirely on how fast the water is arriving, and that is the first thing this page asks you to look at. A flow that does not stop is an emergency: switch the power off, close the cold water valve above the heater, and telephone a plumber straight away. Rheem's own urgent-help page for a leaking water heater sets out that order — turn off the gas, turn off the electricity, turn off the water supply, then place a bucket under the leak and drain the tank through a hose. A slow drip that produces a small puddle overnight is not an emergency, but it is still worth finding today rather than next month, because Rheem also notes that "Even a small drip can worsen quickly. Since water heaters operate under pressure, a compromised tank may suddenly release more water, leading to significant water damage to your home."

My hot water heater is leaking from the bottom. Does that mean I need a new one?

Not necessarily, and "from the bottom" is exactly the description that hides the answer, because water runs downhill. A leak at a connection at the top, a drip from the discharge pipe, and a weeping drain valve all end up as a puddle at the bottom, and none of them is the tank. That is why this page makes you dry everything first and then look at each part in turn. If the body of the tank is wet while every connection above it is dry, the answer is different: Rheem says that pooling water around the tank body "often indicates internal corrosion that has eaten through the metal, and once a tank begins to deteriorate from the inside, replacement becomes the only safe and cost-effective solution". A steel tank that has rusted through is not repairable at any price.

There is a puddle under my water heater but everything looks dry. What is it?

Most often it is condensation, and condensation is not a leak.

A. O. Smith's gas guide is direct about it. The lighting instructions say: "When a gas water heater is first lit and the tank is cold, condensation often forms inside the water heater. You may hear drips or a sizzling sound when the water heater is first lit or, you may see a small puddle on the floor. Condensation is not a leak and will go away once the tank reaches normal operating temperature."

A NOTICE in the operating section says the same thing again: "If the tank is full of cold water, condensation may form inside the water heater. This condensation may drop on the burner causing a sizzling sound. In some cases, you may see a small puddle on the floor." (That NOTICE finishes "Condensation is normal and should go away once the tank reaches its normal operating procedure" — a typo in A. O. Smith's own document, which is why the sentence quoted above is the one this page leans on. We quote what the document says, not what we think it meant to say.)

That is why this page has you switch the heater off, dry everything, and then wait. With no burner and no element running, the heater makes no new condensation, so anything that appears on the paper towel afterwards is a real leak. It is also why a puddle that turns up on the coldest morning of the year, or right after a new heater is installed, is usually nothing at all.

Water keeps dripping out of the pipe that runs down the side of my water heater. Is that normal?

That pipe is the discharge pipe from the temperature and pressure relief valve, and a persistent drip from it is usually a message about your plumbing rather than about the heater. A. O. Smith's gas guide writes that "A small amount of water dripping from the Temperature and Pressure (T&P) Relief Valve usually means the home's water pressure is too high and/or you need a Thermal Expansion Tank", and separately that debris can hold the valve off its seat. The company's electric guide puts the same finding more strictly: it asks not merely for an expansion tank but for one that is, in its words, "properly sized" and charged to match the incoming water pressure. The difference matters, because a tank that is fitted but set wrong drips just the same, and the same guide says so — if the pressure is right, the tank is right and the valve has been cleared of debris and it still drips, "the valve may be broken—have a qualified person replace the T&P relief valve."

The same manufacturer publishes two pressure figures for two different things, and they are worth keeping apart. The electric guide states them as two sentences: "Most codes allow a maximum incoming water pressure of 80 psi. We recommend a working pressure no higher than 50-60 psi." The gas guide carries the identical figures in one sentence. Note the second is a ceiling, not a target: "no higher than". Both are a plumber's measurement and a plumber's adjustment, not yours.

A large flow of very hot water from that pipe is a different and far more serious signal. The manufacturer says it may be due to the tank overheating, and tells you to turn the gas supply off and call a qualified person. Never cap or plug the pipe: operating a water heater without a working relief valve could cause an explosion.

Can I just tighten the fitting myself?

This site does not publish that step, and the reason is not squeamishness. A connection at the top of a water heater may be a dielectric union, a flexible connector, a heat trap nipple or soldered copper, each of which fails differently when it is over-tightened, and there is no torque figure published for any of them that we could trace to a manufacturer. Rule 1 of this site says we do not print a number we cannot trace, so we do not print one here. What the page does give you is worth more than a guess: knowing that the wet part is a connection rather than the tank tells you that you are looking at a small plumbing repair and not a replacement, and it stops a salesperson selling you a heater you do not need.

How long can I leave the water heater switched off while I do this?

As long as you need to. Nothing is harmed by a storage water heater sitting cold with a full tank, and the whole diagnostic depends on it being off, because that is what stops new condensation forming and lets you tell a real leak from a normal one. The one thing that does cause damage is the opposite mistake: putting the power back on when the tank has been drained or has emptied itself through a leak. An electric element that runs dry burns out quickly, which is why A. O. Smith's electric guide says "Do not turn power back on until the tank is completely full of water." If you have closed the cold water valve and drained anything, leave the power off until the plumber has been.

Why does this page tell me to switch the power off before I even look at anything?

Because the moment you are most exposed is the moment before you have learned anything. You are standing on a wet floor, next to an appliance that is still live, about to reach behind it with a flashlight. A. O. Smith's electric guide puts the instruction in the general-risk section rather than in any one procedure: "Disconnect power by opening the circuit breaker or removing the fuses before installing or servicing", and "Use a non-contact circuit tester to confirm that power is off before working on or near any electrical parts." Rheem's emergency page for a leaking water heater has the same ordering — electricity off, then water off. An earlier draft of this page put the electrical warning one step later, after the reader had already been sent to close a valve on a live heater while standing in water, and that draft passed our own automated hazard-placement check, because the check proves that a warning comes before its step and cannot prove that it is about the right step.

Sources

Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.

  1. Tier 1Residential Standard Gas Water Heater Installation Instructions and Use & Care Guide (document 100263112, January 2015)A. O. Smith Corporation · accessed 2026-08-03 · re-verification due 2027-01-30
  2. Tier 1Residential Electric Water Heater Installation Instructions and Use & Care Guide (document 100264218)A. O. Smith Corporation · accessed 2026-08-12 · re-verification due 2027-02-08
  3. Tier 15 Signs Your Water Heater Is Going Bad (And What to Do About It)Rheem Manufacturing Company · accessed 2026-08-12 · re-verification due 2027-02-08
  4. Tier 1Urgent help — water heating self helpRheem Manufacturing Company · accessed 2026-08-12 · re-verification due 2027-02-08
  5. Tier 1How to Flush a Water HeaterA. O. Smith Corporation · accessed 2026-08-04 · re-verification due 2027-01-31

Revision history

Current version 2 · updated 2026-08-12 · next review due 2027-08-12

  1. v2 · 2026-08-12Independent audit. Every number and every quotation on the page was re-fetched from the manufacturer's own document and read here, not taken from the notes field of the source registry, because the notes are the drafter's account of what a source says and that account is the thing under test. The A. O. Smith electric guide (document 100264218, 2,100,586 bytes) and the A. O. Smith gas guide (document 100263112, January 2015) were downloaded again with curl and extracted with pdftotext -layout; rheem.com/urgent-help and Rheem's '5 Signs Your Water Heater Is Going Bad' were fetched again and stripped to text. All five source URLs returned HTTP 200. Six changes, and one place where the drafter was right and the auditor was wrong. 1. A QUOTATION THAT SILENTLY CORRECTED THE MANUFACTURER. The FAQ carried the gas guide's condensation NOTICE inside quotation marks, ending '...once the tank reaches its normal operating temperature.' Page 24 of that document actually ends '...its normal operating procedure.' A. O. Smith has a typo there, and the draft repaired it inside the quotation marks, which makes the sentence ours and not theirs. The FAQ now quotes the lighting instructions on page 22 - 'Condensation is not a leak and will go away once the tank reaches normal operating temperature' - which is verbatim and says the thing plainly, quotes the NOTICE only as far as the document supports, and states the typo rather than hiding the correction. 2. A HAZARD ATTRIBUTED TO A SOURCE THAT SAYS THE OPPOSITE. The WARNING before s18 read 'DO NOT MOVE THE LEVER ON THE RELIEF VALVE. A. O. Smith gives this task to a qualified person.' A. O. Smith does not. Both guides instruct the owner to operate the T&P Relief Valve manually 'at least annually', and the gas guide tells the owner to clear debris by operating it. What A. O. Smith gives to a qualified person is the five-yearly INSPECTION of the valve and its discharge pipe, and the replacement of a broken valve. The instruction not to move the lever during a leak diagnosis stands as our own editorial boundary; the reason given is now the one the manufacturer actually prints - 'The water may be extremely hot and could cause severe burns.' 3. A GAS RESTART WITH NO PROCEDURE AND NO HAZARD, PAST THE PAGE'S OWN BOUNDARY. s26 restored the appliance after a dry result, and its first substep was 'Set the gas control knob to the usual position.' On a gas water heater s2 has already put that knob to OFF, which puts the pilot out; A. O. Smith's lighting instructions are eight steps with a 90-second hold, three attempts, ten-minute waits and an explosion WARNING, and the front page of the document says 'If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or death.' This site's own registry note on the drain article says it does not reproduce a gas-relighting instruction - and then the record told a novice to do it in six words with no notice attached. The substep now refuses the restart and routes it to the label on the appliance, a WARNING sits before s26, and s2 tells the reader before they commit that the burner will need that procedure again. This is the failure the gate cannot see: check 4 proved the placement of every hazard on the page, and there was no hazard here to place. 4. TWO THRESHOLDS PUBLISHED AS MEASUREMENTS. 'Interval between inspections of the relief valve by a qualified person: 5 years' is not what the document says. Both guides say 'At least every five years' - five years is the longest gap allowed, not the interval, and a reader who books it every five years to the day is inside the rule only by luck. It is now 'Maximum interval between inspections...'. The same shape appeared on 'Working water supply pressure A. O. Smith recommends for a house: 50 to 60 psi': A. O. Smith's words are 'We recommend a working pressure no higher than 50-60 psi', so the name now carries 'no higher than' and the FAQ says in as many words that it is a ceiling and not a target. The 80 psi figure was already named as a maximum and is unchanged. 5. THREE SPECIFICATIONS CITED TO THE WRONG ONE OF TWO CITED SOURCES. All three carried source_id aosmith-residential-gas-use-care-manual, while this record's own version 1 note said the figures came from the electric guide, and the registry note on the gas manual says in terms that no pressure figure from it is reproduced. The registry note on the electric guide says the opposite: 'THE THREE FIGURES THIS RECORD PUBLISHES ARE ALL FROM THIS DOCUMENT'. The figures are in fact in both documents - verified in both, this session, at gas guide pages 8 and 27 and electric guide pages 6, 13 and 30 - but the quotation the FAQ prints is the electric guide's two-sentence form, so the citation now points where the quoted words and the audit trail already pointed. Nobody would have been hurt by this one. It is recorded because a citation that disagrees with its own registry note is how a wrong number survives a later re-verification. 6. A COUNT THE PAGE CONTRADICTED ITSELF ON. The title said five origins, the subtitle listed six, and the summary said 'Every one of the five results then routes to a licensed plumber' - which the page's own s26 contradicts, because the condensation result sends nobody to a plumber. Six now, and the summary says which result does not route. WHERE THE DRAFTER WAS RIGHT AND THE AUDIT WAS WRONG. The T&P drip quotation, 'usually means the home's water pressure is too high and/or you need a Thermal Expansion Tank', looked like a trimmed quote, because the electric guide says '...too high or you need a properly sized and pressurized Thermal Expansion Tank' and the dropped words carry real meaning. Page 26 of the gas guide carries the sentence exactly as the FAQ printed it, and/or included. The draft was verbatim and the suspicion was wrong. The FAQ now names the guide and gives the electric guide's stricter wording as well, because an expansion tank that is fitted but wrongly pressurised drips just the same. Also checked and found sound: the two Rheem quotations, verbatim on the live article; Rheem's urgent-help ordering, gas then electricity then water, then bucket and hose; 'Almost all leaks occur at connections and are not a tank leak', in both guides; 'Disconnect power by opening the circuit breaker or removing the fuses before installing or servicing' and 'Use a non-contact circuit tester to confirm that power is off', both in the electric guide's RISKS DURING INSTALLATION AND MAINTENANCE section; 'Do not turn power back on until the tank is completely full of water'; 'Before you call, write down the model and serial number', page 1 of the gas guide; the cap-or-plug explosion warning; and the three consult-the-manufacturer specifications, which publish no digit and are rule 1 working rather than rule 1 failing. No recall, no standard clause and no test result is claimed anywhere on this page, so there was nothing of that kind to check against an official notice. The professional boundary now says 'close the gas supply valve' for an overheating tank rather than 'set the gas control knob to off', which is what A. O. Smith's Emergency Shut down paragraph says: 'turn off the water heater's manual gas control valve and call a qualified person.' STILL OPEN, AND NOT IN THIS AGENT'S SCOPE. The three verified specifications still carry spec_key null, so check 2 raises three warnings and none of the three is cross-checked against data/specs.json. Version 1 said this must be closed before the page publishes; the page published anyway. This session verified all three directly against the manufacturer's own PDF, so the values themselves are sound, but the registry entry is a second pair of eyes the page does not yet have. data/specs.json is a protected registry a delegate may not write. Register the maximum incoming water pressure, the recommended working pressure and the relief-valve inspection maximum interval against aosmith-residential-electric-use-care-manual, then set the three spec_keys.
  2. v1 · 2026-08-12First draft. Scaffolded as doc_type diagnostic per the backlog note, because the whole value of the page is sorting one symptom into results that do not share an answer, and because every result routes to a licensed plumber rather than to a repair this site publishes. SOURCES READ THIS SESSION, IN FULL. A. O. Smith Residential Electric Water Heater Use & Care Guide (document 100264218) and A. O. Smith Residential Standard Gas Water Heater Use & Care Guide (document 100263112) were both downloaded and extracted locally with pdftotext -layout and read directly, because the fetch tool returns only PDF binary structure for these files. Rheem's '5 Signs Your Water Heater Is Going Bad' article and Rheem's Urgent Help page were fetched, and then independently re-fetched with curl and stripped to text so that the quotations are confirmed against the live pages rather than against a summary of them. A. O. Smith's 'How to Flush a Water Heater' support article was re-read and its registered quotations still match. THE HAZARD ORDERING, WHICH IS THE POINT OF THIS RECORD. A previous draft of this topic anchored the electrical WARNING one step too late: the reader was sent to close a valve on a leaking, still-energised heater while standing in water, and only then warned about shock. That draft PASSES gate check 4, because check 4 proves a hazard is placed before its step and cannot prove it is about that step — the gap is documented in CLAUDE.md and pinned by tests/test_hazard_correspondence.py. This draft therefore fixes the step order rather than the hazard position. s1 is 'Set the electrical power to the water heater to off', the electrical WARNING sits before s1, and nothing in the record touches the heater, the water or any valve before it. That ordering is not this session's invention: A. O. Smith's electric guide puts 'Disconnect power by opening the circuit breaker or removing the fuses before installing or servicing' in the general RISKS DURING INSTALLATION AND MAINTENANCE section rather than inside any one procedure, and Rheem's own emergency page for a leaking water heater orders the shutdowns gas, then electricity, then water supply. THE DIAGNOSTIC THAT MAKES THE PAGE WORK. The five-way sort is assembled from separate statements in separate sections of the manufacturers' own documents; no manufacturer document read here carries a leak-origin table, and the assembly is editorial. The mechanism that separates condensation from a leak is a deduction rather than a quotation, and it is recorded here so a later session can challenge it: A. O. Smith states that condensation forms when a tank full of cold water is heated and that it stops when the tank reaches its normal operating temperature. With the power and the gas already off for safety, the heater produces no new condensation, so anything that appears on a dry floor afterwards is a real leak. The safety step and the diagnostic step are the same step, which is why the page can afford to insist on it. NUMBERS PUBLISHED, AND WHERE THEY CAME FROM. Three, all from the A. O. Smith electric guide and all quoted verbatim in the source note: a working water supply pressure of 50 to 60 psi, a maximum incoming water pressure of 80 psi that A. O. Smith attributes to most codes, and a five-year interval for a qualified person to inspect the relief valve and its discharge pipe. The two pressure figures are deliberately given different names and are NOT recorded as a conflict, because they are a recommendation and a maximum for two different things — sourcing.md warns specifically against recording that shape as a disagreement. The same 50-60 psi figure appears three times in the electric guide and three times in the gas guide, so the two documents agree. Three further specifications publish as consult-the-manufacturer with no digit: the pressure rating of the relief valve, the temperature of the water in the discharge pipe, and the quantity of water that makes this an emergency. NOTE FOR THE PUBLISHER. The three verified specifications carry spec_key null, so check 2 reports three warnings and none of the three is cross-checked against data/specs.json. That is deliberate and it must be closed before this page publishes. This session was instructed to write only the record and its sources side file, because several agents are working in the repository at once and data/specs.json is a protected registry a delegate may not write. Register the three values, then set the spec_keys. WHAT WAS LOOKED FOR AND NOT FOUND. No United States government source that sorts a water heater leak by origin was reachable: energy.gov/energysaver/water-heating and energy.gov/energysaver/storage-water-heaters both returned HTTP 404 on 2026-08-12 and are recorded as checked-and-rejected in the sources side file rather than cited through a secondary. The standard governing the relief valve itself (ANSI Z21.22) is a paid document and was not opened, so no clause of it is quoted or paraphrased anywhere on this page. WHAT THE PAGE REFUSES TO DO. The backlog note describes one of the five origins as 'a fitting a reader may tighten'. This draft does not instruct that, and the FAQ says plainly why: a connection at the top of a water heater may be a dielectric union, a flexible connector, a heat trap nipple or soldered copper, and no torque figure for any of them could be traced to a manufacturer. Rule 1 forbids printing one anyway, and 'tighten it until it stops' is exactly the guessed instruction rule 1 exists to prevent. The sorting is published; the repair is not.

Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.

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