Water Heater Replacement in San Antonio, TX

Clear signs a tank has reached the end

• Water is coming from the tank body. This is not repairable. Steel tanks corrode from the inside, and once through, they only get worse.
• Persistently rusty hot water when cold water runs clear.
• Age plus a major fault. A gas valve or a badly scaled tank on a ten-year-old unit rarely justifies the repair.
• Visible corrosion at the fittings, on the jacket, or in the drain pan.
• Repeat failures within a short period.
• Chronic shortfall — the household routinely runs out of hot water even with a correctly functioning unit.

Sizing: the part most often got wrong

Tank heaters are usually judged by capacity, but the more meaningful number is the first-hour rating — how much hot water the unit can actually deliver in an hour of heavy use, combining what's stored with what it can reheat. Two 40-gallon heaters with different recovery rates are not equivalent.

For tankless units, the number that matters is flow rate at a given temperature rise. A tankless heater rated for a certain gallons-per-minute in a warm climate delivers less when the incoming water is colder, which is why winter performance is the case to size for, not summer.

Things worth telling the plumber when sizing:

• How many people live in the home, and when demand peaks.
• Whether you have a large soaking tub or multiple showers likely to run at once.
• Whether the current unit has ever been adequate.
• Whether you are planning a bathroom addition.

Tank, tankless, gas or electric

Neither is automatically the right answer. In San Antonio's hard water, the honest version is that both need maintenance — a tank needs flushing, a tankless unit needs descaling — and a tankless heater installed and then ignored will disappoint.

What a correct installation includes

A replacement is not only about the heater. These elements are routinely part of doing the job properly, and older installations often lack them:

• A drain pan with a routed drain line where a leak would damage the building — attic, upper floor or interior closet installations especially.
• A correctly sized temperature and pressure relief valve with a discharge pipe terminating where required, not capped and not pointed at a wall.
• A thermal expansion tank where the system is closed by a check valve or pressure-reducing valve. Without somewhere for heated water to expand, pressure spikes stress the whole system and can cause the T&P valve to weep.
• Proper venting on gas units, sized and pitched correctly, with adequate combustion air.
• Seismic or securing straps and correct elevation where required by local rules.
• Serviceable shutoffs and unions so the next service visit doesn't require cutting pipe.

Water heater replacement commonly requires a permit and inspection. Confirm with the plumbing professional who will do the work whether a permit applies at your address, and who pulls it.

Getting the most life out of the new unit

• Flush a tank heater on a schedule appropriate for hard water rather than the generic annual advice.
• Have the anode rod checked partway through the warranty period, not after it expires.
• Descale a tankless unit at the interval the manufacturer specifies.
• Keep house pressure within a normal range; ask for it to be measured at installation.
• Keep the area around the unit clear, particularly the combustion air path on a gas heater.
• Register the warranty and keep the invoice — warranty claims usually require proof of professional installation.

Questions worth asking before you commit

1. What first-hour rating or flow rate are you specifying, and why that one for my household?
2. Does the quote include a new drain pan, expansion tank, shutoff and any venting changes?
3. Is a permit required, and is it included?
4. What is the manufacturer's warranty on the unit, and what is your warranty on the labour?
5. Is removal and disposal of the old unit included?
6. What maintenance does this specific model need in hard water, and how often?

Frequently asked questions