What we see locally
Over the past year, we have tracked failed-water-heater calls across Milpitas, Sunnyvale, Fremont, and Palo Alto. About seven in ten have involved Rheem heaters, usually 8 to 12 years old. We have averaged at least one failed Rheem call a day during that period.
That is our service-call mix. It does not tell us how many Rheem, Bradford White, or A. O. Smith heaters are installed in local homes, so it cannot establish a brand-wide failure rate or expected lifespan. We also cannot tell from the brand and age alone why a particular tank failed.
Many homeowners tell us their heater has never had a service visit. That matters when judging an older tank: the manufacturer maintenance guidance below applies to every brand, and anode condition, sediment, venting, and water quality deserve attention before anyone promises that a new label alone will solve the problem.
In one Milpitas garage replacement, a leaking Rheem prompted us to tell the customer to shut off the water supply. We installed a 50-gallon A. O. Smith unit and tested the finished connections. That job shows what a replacement can include; it is not a performance test of 40-gallon models.
Compare models, not just logos
A “40-gallon gas heater” is not one standardized product. A short model, a tall atmospheric-vent model, and a power-vent model may need different space, venting, and installation work. The three examples below are 40-gallon natural-gas, atmospheric-vent, Ultra Low NOx models. Their published first-hour ratings describe hot-water delivery under standardized conditions, not how long the tanks will last in a Milpitas garage.
| Example model | Published first-hour rating | What to confirm on the quote |
|---|---|---|
| Rheem Performance XG40T06EN38U0 Model page ↗ | 71 gallons in Rheem's published model sheet ↗ | Confirm the current model number, dimensions, written warranty, and installed scope. Rheem lists a six-year limited tank-and-parts warranty for this series. |
| Bradford White Eco-Defender URG240T6N Model sheet ↗ | 75 gallons in Bradford White's model sheet | Confirm dimensions and the written warranty for the exact unit. Bradford White sells through plumbing professionals, so ask for an installed quote. |
| A. O. Smith ProLine Master HUC-40 450 Model page ↗ | 83 gallons on A. O. Smith's model page | Confirm fit and total installed cost. The cited model lists an eight-year limited tank-and-parts warranty. |
These are examples from different product lines, not a controlled durability test or a price ranking. Manufacturer information and availability can change. Confirm the exact SKU and written warranty before ordering. Bradford White explains its professional-sales model ↗
Our plumbers generally recommend Bradford White or A. O. Smith unless a customer prefers another brand. That is our shop's preference based on our work, not proof that every Rheem model is inferior. A sound recommendation also has to fit the home's hot-water demand, space, venting, and current installation requirements.
The maintenance question matters with every brand
Before deciding that one manufacturer alone explains an older tank's failure, ask what service it has had. The three manufacturers each recommend routine attention to sediment and tank protection:
- Rheem ↗ describes roughly annual tank flushing, anode inspection, relief-valve checks, and leak checks for traditional tank heaters.
- Bradford White ↗ advises an annual professional check to flush sediment and look for scale or corrosion.
- A. O. Smith ↗ recommends annual anode inspection and includes tank flushing and temperature-and-pressure relief-valve checks in its maintenance guidance.
The exact schedule and procedure depend on the model and water conditions. If a heater has gone years without service, ask a qualified plumber to assess its condition before attempting to drain it or work on gas, venting, or safety components.
Five questions to ask before replacing a 40-gallon heater
- Where is the leak? Water at a connector, valve, or relief line may call for a different repair than a leaking tank.
- How much hot water does the home need? Compare first-hour ratings and your household's peak use, rather than choosing by the “40-gallon” label alone.
- Will the new model fit the existing setup? Have the installer check height, diameter, venting, gas and water connections, and required restraints.
- What does the installed quote include? Ask about removal, new connectors, shutoff and vent work, permits where required, startup testing, and the written warranty.
- What maintenance will you actually do? Put the model-specific service schedule somewhere you can find it after installation.
Before choosing any gas model, check the Bay Area Air District's current Rule 9-6 status ↗ and ask your installer about applicable requirements. Proposed changes were pending when this guide was written in October 2026.
How this guide was put together
The call figures and field preference above come from The Honest Plumber of Milpitas and should be updated as more calls are logged. Model figures and maintenance recommendations come directly from the linked Rheem, Bradford White, and A. O. Smith pages. We compare identified models so a homeowner can ask about the actual unit in a quote. The model table is a starting point for a conversation, not a prediction of service life.
Need help choosing or installing a unit? See our Milpitas water heater repair and installation service.