What is your water heater doing? Pick the closest match.
Tap a symptom for a plain-English next step and how urgent it is. It is a guide, not a diagnosis.
Repair or Replace? 30-Second Check
Four questions give you a rule-of-thumb lean. It is a guide, not a diagnosis. A plumber confirms the cause on site before anything is recommended.
Common Water Heater Problems
Most tank water heater problems fall into a handful of categories: no hot water, not enough hot water, water that is too hot, leaks, noise, smell or color, and safety devices that trip or drip. Each has several possible causes, and the cheapest fix is the one that matches the real cause. That is why we diagnose first and quote second.
A tank water heater is a simple machine: cold water enters near the top and travels down a dip tube to the bottom, where an electric element or gas burner heats it. Hot water rises and leaves from the top. A thermostat controls temperature, a temperature and pressure (T&P) relief valve protects the tank, and a sacrificial anode rod corrodes in place of the tank wall. When one of those parts fails, you get a symptom. The table below links the symptom to its usual suspects.
| Symptom | Common causes | Usually repairable? |
|---|---|---|
| No hot water (electric) | Tripped breaker, failed element, failed thermostat or high-limit switch | Yes |
| No hot water (gas) | Pilot out, failed thermocouple or igniter, gas control valve, blocked vent | Often |
| Lukewarm water | Failed lower element, sediment, thermostat, crossed connections | Often |
| Runs out quickly | Broken dip tube, sediment, failed element, undersized tank | Often |
| Leak at fitting or valve | Loose or corroded connection, failing drain valve, T&P valve | Yes |
| Leak from tank body | Corroded or cracked steel tank | No, replace |
| Rumbling or popping | Sediment on the tank bottom | Often, flush early |
| Rusty or smelly hot water | Spent anode rod, corroding tank, bacteria reacting with the rod | Depends on tank condition |
| T&P valve dripping | High water pressure, thermal expansion, failing valve, overheating | Yes, find the cause |
If the answer is replacement, our water heater installation team explains your options. If you are not sure which situation you are in, use the repair-or-replace check above and then call us.
No Hot Water and Temperature Issues
Your water heater is not producing hot water most often because a power or fuel supply has been interrupted, or because a heating component has failed. The causes differ for electric and gas heaters, so the first question is always: which type do you have?
Electric water heaters: no or little hot water
- Tripped breaker or blown fuse. A heater that trips repeatedly has a real fault, such as a shorted element. Do not keep resetting it.
- Failed heating element. Most tanks have two. An upper element failure usually means no hot water. A lower element failure usually means less hot water that runs out fast.
- Failed thermostat or high-limit switch. The high-limit (ECO) trips when water gets too hot. It can trip because of a fault, not just because it is old.
- Wiring or connection problems. Loose or burned connections at an element or thermostat are a fire risk and need a licensed professional.
Gas water heaters: no or little hot water
- Pilot out. A pilot can go out from a draft, a dirty pilot assembly, or a failing thermocouple or flame sensor. If it keeps going out, there is a cause to find.
- Failed thermocouple or igniter. The part that proves the flame is lit wears out. When it fails, the gas control shuts off the gas on purpose.
- Gas control valve problem. A failed control can stop gas flow or fail to hold temperature.
- Venting or combustion air trouble. A blocked or backdrafting vent can shut a heater down or, worse, push exhaust into the home.
Hot water that is too hot, or swings in temperature
Scalding water is a safety issue. A stuck thermostat, a failed gas control or an overheating element can raise the temperature above the setting. Turn the thermostat down toward 120°F, keep children away from hot taps, and call us. If the T&P valve is dripping at the same time, there may also be a pressure problem, which we cover below.
Hot water that runs out faster than it used to
A broken dip tube sends incoming cold water straight to the top of the tank where it mixes with hot water, so the hot runs out quickly. Sediment, a failed lower element or a heavier household load can do the same. It is worth ruling out a repairable part before assuming the tank is too small. If the heater really is undersized, replacement with a larger or higher-recovery model is the answer.
Leaking Water Heaters: Where the Water Comes From
A leaking water heater can sometimes be repaired, but only if the leak is not coming from the tank itself. Water on the floor does not tell you where it started, so the first job is tracing it to the source.
| Where the water starts | Likely cause | Repair or replace? |
|---|---|---|
| Top of the tank, at the pipe connections | Loose or corroded inlet and outlet fittings, failed flex connectors | Repair |
| Side of the tank, at the relief valve or discharge pipe | T&P valve opening because of pressure, heat, or a worn valve | Repair, and fix the cause |
| Bottom, at the drain valve | Worn or sediment-clogged drain valve | Repair |
| Electric: at an element gasket | Failed gasket or corroded element flange | Repair |
| Under the tank, no visible source | Tank body leak or condensation | Inspect; body leak means replace |
| Tank jacket wet, sides rusted | Corroded steel tank | Replace |
Can a leaking water heater be repaired?
Yes, if the leak is from a fitting, valve, element gasket or connector. No, if the leak is from the tank wall. Once the steel tank has rusted through, there is no safe or lasting patch. Every repair on a failing tank is money spent on something that is about to fail anyway.
Condensation versus a real leak
Some gas heaters, especially high-efficiency models, produce condensation. A few drops that dry on their own may be harmless, but steady water is not. We check before calling it condensation.
Why attic leaks cost more
In many San Antonio homes the water heater sits in an attic or a closet above finished space. A slow leak can soak insulation and drywall long before anyone sees a puddle. If you have a heater in the attic, check the drain pan and pan drain line regularly, and look for ceiling stains below.
Gas and Electric Water Heater Problems
Gas and electric heaters fail in different ways, and the safety risks are different too. Knowing which you have helps you describe the problem and helps us bring the right parts.
What commonly goes wrong
- Pilot assembly, thermocouple or flame sensor wear
- Igniter failure on electronic-ignition models
- Gas control valve faults
- Dirty burner or soot from poor combustion
- Blocked flue or draft problems
- Corroded vent connector or flex connector
What commonly goes wrong
- Burned-out upper or lower element
- Failed thermostat or tripped high-limit
- Loose, burned or corroded wiring
- Element gasket leaks
- Tripped breaker from a short
- Insufficient circuit for the heater's rating
Gas water heaters and your meter
If you smell gas, or if CPS Energy has turned your gas off after a leak, the order of operations matters. The gas utility handles the meter. A licensed plumber handles piping and appliances on your side of the meter. If a leak is found on your property, it must be fixed and tested before service can be restored. See our gas line repair page for what that process looks like.
Electric heaters and your panel
Electric water heaters draw a lot of power. A heater that keeps tripping its breaker, or wiring that feels hot or smells burned, is a fire risk. We repair the water heater and its connections, and if the problem is inside the electrical panel, we tell you to call a licensed electrician rather than guess.
Sediment and Mineral Buildup: The Hidden Cause
San Antonio water is hard, which means it carries dissolved calcium and magnesium. When water is heated, those minerals come out of solution and settle as scale on the bottom of a tank heater and on electric elements. Sediment is one of the most common reasons a heater rumbles, runs out of hot water early, or fails years ahead of schedule.
What sediment does to a tank water heater
- Insulates the water from the burner or element. On a gas heater, the burner has to heat through a layer of scale. On an electric heater, scale can bury the lower element and burn it out.
- Causes rumbling and popping. Water trapped under scale flashes to steam and bursts through.
- Reduces usable hot water. Sediment takes up space in the tank, so there is less room for hot water.
- Hides corrosion. Scale can mask a tank wall that is starting to corrode underneath.
Flushing a tank water heater
Flushing means draining some or all of the water out the drain valve to carry sediment with it. It helps most when it is done regularly, starting while the heater is fairly new. On an old heater that has never been flushed, scale may be hard and packed, and the drain valve may clog or leak after it is opened. That is a good reason to have a plumber do it and be ready with a replacement valve if needed.
The anode rod and the rotten-egg smell
The anode rod is a metal rod that corrodes first so the tank does not. Once it is spent, the tank itself starts to corrode, which is why checking or replacing the rod can extend a heater's life. In some homes, bacteria in the water react with a magnesium anode rod and produce a rotten-egg (hydrogen sulfide) smell in the hot water only. A plumber can recommend the right approach, which may include a different rod material and a flush. If the smell is on both hot and cold water, the cause may be elsewhere.
Water Heater Repair vs. Replacement: How to Decide
The right answer depends on age, condition, the failed part and what the repair costs compared with a new heater. A simple rule: repair a newer heater with a failed part, and replace an older heater with a failing tank.
| Situation | Usually better | Why |
|---|---|---|
| Under about 8 years old, failed element, thermostat, igniter or valve | Repair | The tank is likely sound and the part is inexpensive relative to a new heater |
| 10 to 12+ years old, first repair needed | Compare both quotes | Close call; depends on tank condition |
| Second or third repair on an aging tank | Replace | Repair costs add up and the tank is near the end of its life |
| Leak from the tank body, rust-through, wet insulation | Replace | A failed tank cannot be patched |
| Rusty hot water with a rusting tank | Replace | The lining or tank wall is likely failing |
| Heater is undersized for the household | Replace or upgrade | A repair will not add capacity |
| Failed gas control on an older heater | Often replace | The control can cost a large share of a new heater |
A common rule of thumb
Many plumbers use a simple guide: if the repair costs more than roughly half the price of a new heater and the heater is past the middle of its life, replacement is usually the better value. It is only a guide. We always show you the numbers and let you decide.
What a typical tank lasts
Standard tank water heaters commonly last roughly 8 to 12 years. Hard water, high pressure, a missing expansion tank, a hot attic and skipped maintenance can shorten that. Good maintenance can help a heater reach the upper end of the range.
When upgrading beats repairing
- You need more hot water than the current tank gives.
- You want lower operating costs with a heat pump model.
- You want endless hot water and have the gas and venting for it. See our tankless water heater page.
- The heater is in a hard-to-reach spot and you do not want to repeat a difficult repair.
What to Do Right Now When Your Water Heater Fails
If your water heater is leaking, scalding or not working, these steps keep you and your home safe until help arrives.
- Check for danger first.If you smell gas or see water near the electrical panel, leave the home and call 911 and CPS Energy before doing anything else.
- Turn the heater off.For gas, turn the gas control to off or pilot. For electric, switch off the dedicated breaker. Never leave an electric heater on if the tank may be empty.
- Close the cold water supply to the heater.The shutoff valve is usually on the cold pipe above the tank. If it will not turn, shut off the main water valve to the house.
- Contain the water.Use towels, a wet vac or buckets. Move belongings out of the path. Do not use a vacuum near electrical outlets in wet areas.
- Take photos.Photograph the heater, the data label and the water damage. It helps your estimate and any insurance claim.
- Call us at (210) 898-9754.Tell us the type of heater, its age and where the water starts. Text photos if you can.
If the leak is large or the damage is spreading, see our emergency plumber page.
Noises, Smells and Discolored Hot Water
Strange noises, smells and colors are your water heater's way of telling you something has changed. Many are early warnings that are cheaper to deal with now than later.
Why is my hot water discolored?
Rusty, brown, orange or yellow hot water usually points to corrosion. If the discoloration appears only on the hot side, the tank lining, a spent anode rod or iron-bearing scale inside the tank is the likely source. If it also appears on cold water, the problem is more likely in the supply piping. A quick test: fill a white bucket from the cold tap, then from the hot tap, and compare. Take a photo and send it to us. If the pipes are the source, our repiping page explains when old pipes need replacing.
Why does my hot water smell like rotten eggs?
A rotten-egg smell in hot water only is commonly caused by bacteria reacting with the anode rod inside the tank. It is a nuisance rather than an emergency, but it is worth addressing. A flush, a different anode rod, or both may help. If the smell is also on cold water, or if you smell actual gas, treat that as a different issue. A gas smell is an emergency and means leave and call 911 and CPS Energy.
Rumbling, popping and crackling
These are sediment sounds. They often start gradually, and they are a sign the tank needs attention. Left alone, the bottom of the tank can overheat and the heater can fail sooner.
Banging pipes
A bang when a faucet or appliance shuts off is usually water hammer, not a heater problem. High pressure or a missing air chamber is often the cause. See our water pressure repair page for diagnosis.
Hissing, sizzling and steaming
Water dripping onto a hot burner or element, or the T&P valve venting, can cause these sounds. Turn the heater off and keep clear. Steaming from the discharge pipe is a safety signal that needs prompt attention.
T&P Valves, Expansion and Water Pressure Problems
A dripping relief valve is not just a nuisance. It is a safety device telling you that pressure or temperature has risen beyond a safe point. Replacing the valve without finding the cause often leads to the same drip again.
Why a T&P valve drips
- High incoming water pressure. SAWS pressure in the service area can range widely, and the recommended maximum inside a home is around 80 psi. A failing pressure regulator can let pressure climb.
- Thermal expansion in a closed system. Water expands when heated. If a backflow device or regulator keeps it from flowing back, pressure rises with each heating cycle unless an expansion tank absorbs it.
- An overheating tank. A failed thermostat or control can push temperature too high.
- A worn or sediment-coated valve. The valve itself may be failing.
What we check
We measure static and working water pressure, check for an expansion tank and its air charge, test the thermostat and heating, and inspect the discharge pipe. If pressure is the cause, we may recommend pressure regulator replacement along with the repair so the problem does not come back.
Our Water Heater Repair Process
You should know exactly what happens when a plumber comes to your home. Here is our process from first call to finished repair.
- You call or text.Tell us the type, age and symptoms. Photos of the data label and the problem area help us bring the right parts.
- Safety check on arrival.We look for gas odor, water near electrical equipment, venting problems and visible damage before anything else.
- Diagnosis.We test the heating components, controls, valves, pressure and venting to find the real cause rather than guess.
- Plain-English explanation.We show you what failed, what the options are, and whether repair or replacement makes sense.
- Written estimate.You get a written estimate before any work begins, and nothing starts without your approval.
- Repair.We replace the failed part and any worn connectors or valves that put the repair at risk.
- Testing.We check for leaks, correct operation, temperature, venting and, on gas heaters, gas tightness and combustion.
- Cleanup and walkthrough.We clean the area, explain what was done, and tell you what to watch for.
Water Heater Repair Cost Factors in San Antonio
Water heater repair cost depends on which part failed, how hard it is to reach, and whether the repair is worth making on an older tank. The ranges below are general industry ballpark figures for planning only. They are not a Stark quote, and your written estimate governs.
| Repair type | General industry ballpark | What moves the price |
|---|---|---|
| Electric element or thermostat | About $150 to $450 | Part type, upper or lower, access |
| Gas thermocouple, igniter or flame sensor | About $150 to $450 | Model, part availability, access |
| T&P relief valve and discharge line | About $150 to $400 | Discharge routing, root cause |
| Drain valve replacement | About $150 to $350 | Scale, access, whether the tank is drained |
| Gas control valve | About $300 to $700 | Model, age of the tank |
| Flush and anode inspection | Varies with scale and age | Sediment level, valve condition |
| Leaking tank body | Replacement, not repair | See installation cost factors |
What changes the price
- Whether the heater is in an attic, closet or garage
- Whether parts are in stock for the specific model
- Whether connectors, valves or vent pieces also need replacing
- Whether a permit is needed (repair usually does not need one; replacement typically does)
- The time of day, if the call is urgent
San Antonio Factors: Hard Water, Pressure, Heat and Older Homes
Local conditions change how water heaters wear out and what repairs they need. A plumber who knows San Antonio looks for these first.
- Hard water. It leaves scale in tanks and on elements, shortening heater life. Regular flushing and a softener help.
- Variable water pressure. SAWS pressure can range widely depending on where you live, and the recommended maximum inside a home is around 80 psi. A pressure regulator that has failed will stress your heater and relief valve.
- Hot attics and garages. Heat speeds up wear on valves, connectors and electrical parts.
- Older homes. Many older homes have galvanized or mixed piping, old shutoff valves and tight closets. Corroded connectors and shutoffs often need replacement during a repair.
- Slab foundations and clay soils. Shifting soil can stress pipes and fittings, which can show up first near the heater.
Need help finding a pressure problem that is not coming from the heater? See our water pressure repair page.
Seasonal Water Heater Issues in San Antonio
San Antonio does not have long winters, but cold snaps and summer heat both put stress on water heaters. Here is what to watch for through the year.
Winter
Colder incoming water means the heater works harder, and usage goes up with guests and holidays. Freeze events can damage exposed pipes and outdoor or unconditioned installations. Insulate exposed hot and cold pipes, know where your main shutoff is, and remember the February 2021 freeze when planning. Drafts can also blow out gas pilots.
Spring
A good time for a checkup after the cold months. Look for drips, rust, stains, and a pilot that has become unreliable. Schedule a flush and anode rod check before summer.
Summer
Hot attics bake valves, connectors and wiring. Heavy summer use and visitors raise demand. A slow leak above a ceiling can do major damage before it is seen, so check pans and ceilings.
Fall
The best time to replace an aging heater, before winter demand and the holiday rush. Test your CO alarms before heating season and check that the vent connection is secure.
Checklists: Maintenance, Before We Arrive and Questions to Ask
Annual water heater maintenance checklist
· Tip: screenshot this list.
Before we arrive
· Tip: screenshot this list.
Questions to ask any plumber
· Tip: screenshot this list.
Why You Should Not Repair a Water Heater Yourself
Some homeowners can safely flip a breaker or look at a pilot window. Most water heater repairs, however, involve gas, 240-volt electricity, scalding water or combustion, and mistakes can be serious.
- Gas leaks and carbon monoxide. A bad connection or blocked vent can be deadly and may not smell obvious.
- Electric shock and fire. Heater circuits carry high current. Wrong wiring or loose connections can start fires.
- Scalding. A tank holds a lot of very hot water.
- Tank explosion risk. Defeating or blocking a T&P valve can let a tank over-pressurize.
- Water damage. A botched drain valve or fitting can flood an attic or closet.
- Voided warranty and insurance problems. Unlicensed work can complicate claims.
In Texas, plumbing work is performed by licensed plumbers, and a gas appliance connection is not a place to experiment. You can verify any plumber at tsbpe.texas.gov. If you are comfortable doing a simple visual check, our checklists above show what is safe. For everything else, call us.
How Our Estimates Work: No Surprises
The biggest worry homeowners have about a repair call is the unknown cost. Here is how we handle it.
- Diagnosis before price. We find the cause, then quote the fix.
- Written estimate before work. The estimate lists parts, labor and any permit or add-ons.
- Your approval first. Nothing starts until you say yes.
- Honest repair or replace advice. If the tank is failing, we say so and show you both options.
- If scope changes, we stop and talk. No add-ons appear on the final bill that you did not approve.
- Warranty in writing. Parts and labor terms are on your estimate.
We are located at 1011 Ada St, San Antonio, TX 78223, and you can verify our license through the Texas State Board of Plumbing Examiners before you book.
Emergency No-Hot-Water and Leaking Heater Calls
A heater that is flooding a closet or leaving a family without hot water in cold weather needs help fast. Call (210) 898-9754 and tell us what is happening. We will explain the earliest arrival we can offer and what to do until then.
- Large leak: shut off the cold supply to the heater, turn off the gas or breaker, and call.
- No hot water: tell us gas or electric, the age, and whether there is any water around the tank.
- Gas smell: leave, call 911 and CPS Energy first, then call us once safe.
For flooding from pipes rather than the heater, see our emergency plumber page.
Water Heater Myths vs. Facts
| Myth | Fact |
|---|---|
| A leaking water heater can be patched. | A leak from the tank body cannot be repaired. Fitting and valve leaks can. |
| A dripping T&P valve is normal. | It signals pressure or temperature trouble and needs a cause found. |
| Turning the thermostat up gives more hot water. | It mostly raises scald risk and energy use. |
| Flushing fixes any old heater. | It helps but cannot repair a corroded tank. |
| Relighting the pilot over and over is fine. | A pilot that keeps going out has a cause. Do not keep relighting it. |
| Rusty hot water always means the pipes are bad. | If only hot is affected, the heater is a common cause. |
| Rotten-egg hot water means a sewer problem. | It is often a reaction in the tank, not the sewer. |
| Repair is always cheaper than replacement. | On an old tank, repeat repairs often cost more over time. |
Water Heater Repair FAQs for San Antonio Homeowners
Why is my water heater not producing hot water?
Your water heater is most often not making hot water because of a tripped breaker, failed heating element or thermostat on an electric model, or a pilot, thermocouple, igniter or gas control problem on a gas model. A broken dip tube or heavy sediment can also reduce hot water. Check for water around the tank first, then call us for a diagnosis.
Can a leaking water heater be repaired?
It depends on where the leak starts. Leaks from a fitting, drain valve, T&P valve or element gasket can be repaired. A leak from the tank body means the steel tank has failed and cannot be patched, so replacement is needed. Turn off the heater and the cold water supply, then call us for a written estimate.
Why is my hot water discolored?
Rusty or brown hot water usually points to corrosion inside the water heater, such as a spent anode rod or a failing tank lining. If cold water is discolored too, the supply pipes are the more likely source. Compare hot and cold in a white bucket and send us a photo so we can tell which it is.
How much does water heater repair cost in San Antonio?
Many common repairs, such as an element, thermostat, igniter or relief valve, fall in a general range of about $150 to $450, while a gas control valve can cost more. Price depends on the part, access and heater age. We give a written estimate before work, and your estimate governs, not these general ranges.
Should I repair or replace my water heater?
Repair a newer heater with a failed part, and consider replacement for a heater over 10 to 12 years old, with a leaking tank body, rust, or repeated repairs. A common rule is that if repair costs over about half of a new heater and the tank is aging, replacement is the better value. We show both quotes.
Why does my pilot light keep going out?
A pilot that keeps going out usually points to a dirty pilot assembly, a failing thermocouple or flame sensor, a draft, or a venting or gas supply problem. Do not keep relighting it. If you smell gas at any time, leave and call 911 and CPS Energy. Otherwise call us to check the cause safely.
What should I do if my T&P valve is dripping?
Do not cap or plug it. A dripping T&P valve usually means high water pressure, thermal expansion, an overheating tank or a worn valve. Lower the thermostat toward 120°F and call us. We test pressure, check for an expansion tank and replace the valve if needed.
How long do water heaters last?
Tank water heaters commonly last about 8 to 12 years. Hard water, high pressure, a hot attic, a missing expansion tank and skipped maintenance can shorten that. Flushing the tank and checking the anode rod can help a heater reach the upper end of the range.
Why does my hot water smell like rotten eggs?
A rotten-egg smell in hot water only is commonly caused by bacteria reacting with the anode rod in the tank. A flush, a different anode rod, or both may help. If you smell gas rather than a sulfur odor, that is an emergency: leave and call 911 and CPS Energy.
Why is my water heater rumbling or popping?
Rumbling and popping are usually sediment on the bottom of the tank trapping steam bubbles. San Antonio hard water makes this common. A flush can help if the buildup is not too hard. If the heater is old, discuss repair versus replacement, since the tank may be nearing the end of its life.
Is it safe to reset my electric water heater myself?
You can check whether the breaker has tripped and reset it once. If it trips again, stop and call us, because a repeat trip means a real fault such as a failed element or wiring problem. Do not remove access panels or touch wiring on a live heater.
Do you repair both gas and electric water heaters?
Yes, we repair gas and electric tank water heaters. For on-demand units, see our tankless water heater page. We confirm the type, age and symptoms when you call, and we tell you honestly if replacement is the better choice for your situation.
What if I smell gas near my water heater?
A gas smell is an emergency. Leave the home right away, avoid switches, flames and phones indoors, and call 911 and CPS Energy from a safe distance. Do not try to find or fix the leak yourself. After the area is safe, a licensed plumber can repair the piping and heater connections.
About This Page and Our Sources
Sources and further reading:
- U.S. Department of Energy: Storage Water Heaters — how tank heaters work and basic maintenance
- U.S. Department of Energy: Water Heating — efficiency and temperature guidance
- ENERGY STAR: Residential Water Heaters — efficiency labels
- Texas State Board of Plumbing Examiners — verify a plumber's license
- San Antonio Water System (SAWS) — water quality and pressure information
- CPS Energy — natural gas safety and service restoration
- City of San Antonio Development Services — permit information
Costs, timelines and code requirements vary by home, equipment and the City of San Antonio permit rules in effect at the time of the work. Nothing on this page replaces an on-site inspection by a licensed plumber. Stark Plumbing Solutions is not affiliated with SAWS, CPS Energy or any manufacturer named on this page.
