Water on the floor under a heater is not one problem. It is the relief valve, a connection, or the tank itself, and only one of those means the heater is finished.
Water on the floor under a water heater is not one problem. It is three, they look identical from the doorway, and only one of them means the heater is finished. Before anyone quotes you a replacement, find out which pipe the water is actually coming from. It takes a towel and about ten minutes.
Close the cold water valve on the line feeding the heater. That valve exists by code: the 2021 International Plumbing Code, which the City of Leander adopted with local amendments by Ordinance No. 25-034-00, requires the cold water branch line from the main supply to each water heater to have a valve located near the equipment and serving only that heater, with access on the same floor level as the heater it serves. Closing it takes house pressure off the leak and leaves cold water running everywhere else.
If that valve is seized or will not hold, shut off the main instead and accept losing water to the whole house for an hour. Either is better than letting a tank feed a leak.
Leave the gas control alone. If you smell gas at any point, stop, leave the building, and read the gas section at the bottom of this page before you do anything else.
For an electric heater, the code requires a means of disconnecting the system from its energy supply, and for every other type a separate valve to shut off the fuel supply. Switching off an electric heater's breaker is reasonable if the panel is dry and you can reach it without standing in water. If you cannot do it dry, leave it.
Dry everything, put newspaper or paper towel under the heater and along the discharge pipe, and come back in an hour. Where the paper is wet first is the answer.
| Where the water appears | What it is | What it means |
|---|---|---|
| From the open end of a pipe near the floor | The relief valve discharging | The valve is working. Something else caused it to open |
| At a threaded fitting on top of the heater | The cold inlet or hot outlet connection | A fitting. Repairable with the heater in place |
| At the valve low on the tank body | The drain valve | Usually a washer or a seat. Repairable |
| From the body or seam of the tank | The tank shell itself | No repair. Plan a replacement |
| In the pan, source not obvious | Anything above it | Dry the pan and repeat the test before deciding |
That open-ended pipe is the discharge line for the temperature and pressure relief valve, and water coming out of it is the safety device operating rather than a failure. The code requires every storage water heater operating above atmospheric pressure to carry an approved self-closing levered pressure relief valve and temperature relief valve, or a combination of the two.
The discharge pipe is built so you will notice. The code requires it to flow by gravity, to carry no valves and no tee fittings, not to be trapped, to have no threaded connection at its end, and to terminate not more than 6 inches above the floor at a point that is readily observable by the building occupants. Every one of those rules exists so the pipe cannot be capped, plumbed into a drain, or hidden.
So treat a discharging relief valve as a report, not as the fault. Relief valves are rated to a temperature setting of not more than 210 degrees Fahrenheit and a pressure setting not exceeding the manufacturer's rated working pressure or 150 psi, whichever is less, so a valve that opens has seen one of those. The code also states plainly that the relief valve must not be used as a means of controlling thermal expansion, which is the usual underlying cause on a house with a closed system. Repeated discharge is a system problem to diagnose, and replacing the valve alone just removes the warning.
A pan is containment, not a fix. The code requires a storage tank-type water heater installed where leakage will cause damage to sit in a pan, and requires that pan to be drained by an indirect waste pipe of not less than 3/4 inch diameter, terminating over a waste receptor or floor drain, or outside the building between 6 inches and 24 inches above the adjacent ground.
Two things follow from that. A pan with standing water in it means the drain is blocked or was never run, and the pan is now a reservoir rather than a safeguard. And where a pan drain was not previously installed, the code does not require one for a replacement water heater, so plenty of Leander houses have a pan that drains nowhere by design. If yours is one, the pan buys you minutes, not days.
A leak from an attic heater damages the ceiling below it before anyone sees water, which is why the access requirements matter to you and not just to the installer. The code requires an attic containing a water heater to have an unobstructed passageway not less than 30 inches in height and 22 inches in width and not more than 20 feet long, with a level service space of not less than 30 inches by 30 inches at the service side of the heater.
If your attic heater does not have that, servicing it costs more and takes longer, and that is worth knowing before a failure rather than during one. The code's general rule is the same point: water heaters must be located and connected so as to provide access for observation, maintenance, servicing and replacement.
Natural gas is colorless and odorless, and the rotten-egg odorant is added so that a leak can be recognized, as the City of Richmond explains in its gas safety guidance. The same guidance notes a leak can also show as a white cloud or bubbles in standing water, or sound like roaring, hissing or whistling.
The City of Midland tells residents who suspect a natural gas leak indoors or outdoors to leave the area immediately and contact the gas leak emergency number once safe. The City of Houston adds the part people get wrong on the way out: do not use electric switches, telephones or cell phones, because any of them could cause a spark. Call from a safe location, call 911, and call your gas utility's leak hotline. The Railroad Commission of Texas publishes service interruption contact numbers for every natural gas distribution company operating in Texas.
Nothing on this page is an instruction to work on a gas line, a gas control valve or a flue. Gas-fired water heaters must conform to the International Fuel Gas Code, and that work belongs to a licensed plumber.
Texas Occupations Code Chapter 1301 governs plumbers and defines the responsible master plumber: the licence holder authorized to obtain plumbing permits who assumes responsibility for the plumbing work performed under that licence. Before anyone opens a water heater in your house, you can check them: the Texas State Board of Plumbing Examiners publishes a free public licence search showing a licence type, its status and any disciplinary history.
Vaquero Plumbing is family-owned, works under licence RMP 15304 and backs its work with a two-year warranty. We diagnose and replace water heaters across Leander and the surrounding cities, and our water heater service starts by finding which of the three leaks you actually have. The office is open Monday to Friday 8:00 to 5:30 and Saturday by appointment. If a tank is actively emptying into the house, shut the cold supply, stop using hot water and call 512-893-8705 or use our emergency page.
The cold water valve on the line feeding the heater. The 2021 International Plumbing Code, which Leander adopted with local amendments by Ordinance No. 25-034-00, requires the cold water branch line to each water heater to have a valve located near the equipment, serving only that heater, with access on the same floor level as the heater it serves. Closing it stops the house pressure feeding the leak while leaving cold water on everywhere else. If that valve will not hold, shut off the main instead. Leave the gas control alone.
That pipe is usually the relief valve's discharge line, and water coming out of it is the valve doing its job rather than a failed tank. The code requires that discharge pipe to run full size, flow by gravity, carry no valves or tee fittings, and terminate not more than 6 inches above the floor at a point readily observable by the occupants, which is exactly so that you notice this. A relief valve that discharges repeatedly is reporting excess temperature or pressure, and the code is explicit that the relief valve must not be used as a means of controlling thermal expansion. The valve is the messenger. Something else is the problem.
It depends entirely on where the drip is. A weeping connection at the cold inlet or hot outlet is a fitting, and it is repairable with the heater in place. Water appearing from the body of the tank itself is corrosion through the shell, and there is no repair for that. The honest test is to dry everything, put paper down, and look again in an hour. If the water returns from the tank seam rather than from a fitting or the discharge pipe, plan on replacement rather than a repair.
Leave the building and call from somewhere else. The City of Midland tells residents who suspect a natural gas leak indoors or outdoors to leave the area immediately and contact the gas leak emergency number once safe. The City of Houston adds not to use electric switches, telephones or cell phones on the way out, because any of them could cause a spark, and to call both the gas utility's leak hotline and 911 from a safe location. The Railroad Commission of Texas publishes service interruption numbers for every natural gas distribution company in Texas. Do not touch the gas control, and do not go back in to try anything.
Yes. Vaquero Plumbing works in Leander, Liberty Hill, Cedar Park, Round Rock, Georgetown and Austin, and water heater work runs from diagnosing a relief valve through full replacement under licence RMP 15304. The office is open Monday to Friday 8:00 to 5:30 and Saturday by appointment, and the number is 512-893-8705.
From leaks and clogs to water heaters and repipes, our family-owned crew is ready with same-day service and honest pricing.