Repair it if the tank is sound, the unit is under about 10 years old, and the fix costs less than half of a new heater. Replace it if the tank itself is leaking, it is past 10 to 12 years, or repairs keep stacking up. San Diego's hard water tends to push tank heaters toward the replacement side sooner.
Where exactly is the water coming from?
This is the first and most important question, because it often settles the decision on its own. Water around the base of a heater can come from several places, and only one of them is fatal to the unit.
- A fitting, supply connection or valve on top. Usually repairable. Loose or corroded connections are routine fixes.
- The temperature and pressure relief valve or its discharge pipe. The valve may be failing, or it may be doing its job because pressure or temperature is too high. Either way it calls for a diagnosis, not a new heater.
- The drain valve near the bottom. Often replaceable.
- The tank shell itself. When the steel tank rusts through, HomeGuide notes that full replacement is usually the only real option. There is no lasting patch for a corroded tank.
If you are not sure where the water is coming from, dry the area, put down a towel and watch. A plumber can confirm with leak detection if the source is hidden behind a wall or under the floor.
Which repairs are usually worth doing?
Most water heater parts are inexpensive. The cost is mostly the visit and the labor. HomeGuide's 2026 figures put a typical tank repair between $150 and $700, with an average around $455. Common parts, installed, look like this:
| Part or service | Installed cost (HomeGuide, 2026) | Typical symptom |
|---|---|---|
| Thermocouple | $100 to $325 | Gas pilot will not stay lit |
| Heating element | $100 to $350 | Electric heater runs lukewarm or cold |
| Thermostat | $100 to $350 | Water too hot or not hot enough |
| Gas control valve | $150 to $550 | Burner will not light or cycle correctly |
| Anode rod | $150 to $350 | Rotten-egg smell, early corrosion |
| Pressure relief valve | $50 to $300 | Dripping discharge pipe |
| Dip tube | $100 to $300 | Hot water runs out fast, plastic bits in aerators |
| Tank flush | $75 to $250 | Popping or rumbling sounds |
On a heater that is a few years old, any of these is a reasonable repair. The water heater repair page covers how a plumber diagnoses each one.
When are you better off replacing it?
HomeGuide suggests considering replacement when a unit is older than 10 years or when a repair would cost more than half the price of a new heater. The U.S. Department of Energy puts the life of a storage water heater at 10 to 15 years. Other reasons to lean toward replacement:
- Rust-colored hot water while the cold side runs clear, which points to corrosion inside the tank.
- A second or third repair within a year or two.
- A heater too small for the household, so people are already timing showers around it.
- An older gas unit with a standing pilot that you would like to move away from.
Age is easy to check. The manufacture date is usually coded into the serial number on the label, and most brands explain the code on their websites.
What can you check before calling anyone?
A few no-hot-water problems have simple causes, and ruling them out keeps the visit focused.
- Electric heaters: look at the breaker panel. A tripped breaker can be reset once; if it trips again, leave it off and call a plumber, because something is drawing too much current.
- Gas heaters: look through the sight glass near the bottom of the unit to see whether the pilot or burner is lit. Follow the relighting steps printed on the label only if you do not smell gas.
- Temperature setting: make sure the dial was not bumped to vacation or a low setting.
- Active leak: turn off the cold supply valve above the heater, then shut off power at the breaker or set the gas control to pilot or off.
Note what you find. Telling the plumber that the breaker tripped twice, or that the pilot lights and then goes out, speeds up the diagnosis and can shorten a billed hour.
Does San Diego water wear tanks out faster?
Hard water is one of the main reasons local heaters fall short of their expected life. The City of San Diego's 2025 water quality report shows total hardness averaging about 237 to 243 mg/L, roughly 14 grains per gallon, from its three treatment plants. Helix Water District, which serves La Mesa, Lemon Grove and parts of El Cajon and Spring Valley, reports plant water averaging about 12 grains per gallon. Escondido reports an average of 215 mg/L, and Sweetwater Authority's 2022 report shows an average of 196 ppm.
When that water is heated, calcium and magnesium settle to the bottom of the tank as sediment. The layer insulates the water from the burner, making the heater work harder and louder. A yearly flush helps, and so does checking the anode rod, the sacrificial metal rod that corrodes so the tank does not. HomeGuide lists the part alone at $20 to $50. A water softener reduces scale across the whole house, and the San Diego hard water guide compares the options.
What does a replacement cost?
HomeGuide's 2026 data puts a standard 40 to 50 gallon tank, installed, at $600 to $3,100. Several line items can sit on top of the base price:
- Removal and disposal of the old unit: $75 to $500, sometimes included.
- Expansion tank: $100 to $400, when the plumbing system needs one.
- Permits: $50 to $200.
- Code updates such as new venting, valves or seismic straps: $75 to $500 or more.
For a wider look at how plumbing bills are built in the county, see what plumbers charge in San Diego. Details on the install itself are on the water heater replacement page.
What permits and rules apply?
City of San Diego
The City's Development Services Department allows a simple No-Plan Plumbing/Gas Permit, issued online, for replacing a water heater on a non-historic property. Tankless units are excluded from that shortcut, and historic properties need a Plan permit.
Other cities and unincorporated areas
Chula Vista requires a plumbing permit for water heater work, including the vent. La Mesa's homeowner permit guidance also states that water heater replacement needs a permit; see replacing a water heater in La Mesa for local details. In unincorporated communities such as Ramona and Spring Valley, the County of San Diego Planning & Development Services Building Division issues permits.
Earthquake strapping
California Health and Safety Code section 19211 requires new, replacement and existing residential water heaters to be braced, anchored or strapped against earthquake motion, using the California Plumbing Code as the minimum standard. When you sell a home, the seller must certify in writing that the heater meets this requirement. A proper replacement should include compliant straps.
Should you switch to a different type?
Replacement is the natural moment to reconsider the type of heater. HomeGuide lists tankless units at $1,400 to $5,600 installed and hybrid heat pump models at $2,000 to $4,600. A tankless unit saves space and can last longer, but in the City of San Diego it needs a Plan permit and often new venting or a larger gas line. Read tankless vs tank heaters for San Diego homes before you decide, or see the tankless installation page for what the work involves. If your home is in South Bay, the Chula Vista water heater page has local notes.
If you have a gas water heater
A gas heater that smells of gas, or a pilot area that smells strongly when you are near it, is a safety issue before it is a repair question. Leave the house, then call 911 and SDG&E at 1-800-611-7343 from outside. Some homes use propane instead; your gas bill shows which company supplies you. The gas leak safety guide has the full steps.
Frequently asked questions
How long should a water heater last in San Diego?
Can a leaking water heater tank be repaired?
Do I need a permit to replace a water heater?
Sources
- HomeGuide: Water heater repair cost (2026 cost guide)
- HomeGuide: Water heater installation or replacement cost (2026 cost guide)
- U.S. Department of Energy, Energy Saver: Tankless or demand-type water heaters
- City of San Diego Public Utilities: Annual drinking water quality report (2025)
- Helix Water District: Water quality report (2025 data)
- City of Escondido: Water quality report (2025)
- Sweetwater Authority: 2022 water quality report
- City of San Diego Development Services: Plumbing/Gas permit
- City of Chula Vista Development Services: Utility permits
- City of La Mesa: Permits for homeowners
- County of San Diego Planning & Development Services: Building Division
- California Health and Safety Code section 19211, water heater bracing (Justia, 2023 code)
- SDG&E: Gas safety
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