The question Atherton callers ask most is whether a large home needs more than one water heater. Often it does. With several bathrooms in use at once, soaking tubs and a guest or pool house on the same property, a single standard tank falls behind, and bathrooms far from the heater wait a long time for hot water. Two heaters, tankless units per wing or a large high-recovery tank with recirculation are the usual answers, and the fuel available decides which. Each building's heater is its own job, so say which one is giving trouble when you call, and a photo of each rating plate helps the technician plan.
Atherton homes and heaters
When the Fair Oaks area incorporated in 1923, it could not keep that name, which another California town already used, so residents honored Faxon Dean Atherton, one of the area's early landowners. The town incorporated on September 12, 1923. This page covers ZIP code 94027.
Homes are mostly large single-family houses on generous lots, many extensively rebuilt, with basements, guest houses and pool houses. Natural gas heats water in most, often through two heaters or tankless units with a recirculation loop, while guest and pool houses may run electric units of their own. Heat pump models are a growing question at replacement. The water is fairly soft, so heaters wear more from age and heavy use than from scale.
Room, air and a circuit are the keys.
Cold inlet water and winter recovery in Atherton
Winter in Atherton is mild, but the water entering the heater is still colder in January than in late summer. Every gallon needs more heat, so a tank's recovery slows and a large household's morning can outrun it, particularly when several bathrooms, a tub and a laundry are running together.
Long pipe runs in a big house add to the effect. By the time hot water reaches a far wing, the pipe has shed heat, and in winter that loss is greater. A recirculation loop helps, but a pump running around the clock wastes energy, so a timer or on-demand control is usually better, and insulating accessible pipe cuts the loss further.
Before adding capacity, have each heater checked: a broken dip tube, a weak burner or a recirculation pump pulling cooled water back too fast can each make a well-sized system seem short. Where the heaters are sound, the replacement is sized for the coldest morning and the property's busiest hour, allowing for the guest house and any outdoor showers on the same system.
Tankless sizing at a winter inlet temperature
A tankless unit's output is fixed, so the colder the incoming water, the fewer fixtures it can serve at once. A unit that handles three showers on a September morning may manage two in January, which is why installers size from the coldest water the unit will see, not a summer figure.
Large Atherton homes often use two units side by side, linked to share the load, or one unit per wing. Each needs a gas line sized for full output, and the meter and main line must carry every unit plus the furnace, range and pool heater together, so the gas supply is checked first.
Each unit also needs its own vent, a condensate drain for condensing models and service valves for descaling. Soft water means long gaps between descales, but they still matter, and the first service sets the interval. Where a recirculation loop runs through a tankless unit, a compatible model or settings avoid short-cycling.
Both options, priced side by side.
Basement mechanical rooms
Many rebuilt Atherton homes put the water heaters in a basement mechanical room with the furnace and other equipment. It keeps noise and equipment out of the living space, but a slow leak below grade can go unnoticed, and a finished basement has a great deal to lose.
A drain pan piped to a safe spot for each heater, leak alarms that alert a phone or the home's system and a working floor drain are the first protections. Keep storage away from the heaters and their air supply, and keep the stairway clear, since any replacement travels that route, often with two technicians.
Venting from a basement runs longer than from a garage, often rising through the house or leaving through a side wall, and combustion air has to reach the room. At replacement, the installer checks both before recommending a model, and explains how a heat pump unit's air needs would fit the space. A room that's tight on air may suit a sealed-combustion or tankless model better.
Strapping in Atherton
The tank is fastened to the structure with straps or a bracing kit so the supply lines aren't left to take the strain. A filled tank carries a lot of weight high up, so a secured tank stays upright if it is jolted and keeps its gas, water and vent lines intact. It's part of every Atherton installation.
Strapping is straightforward on a garage wall with exposed studs, and a finished wall may need blocking first. A basement heater against a concrete wall needs masonry anchors, and where two tanks stand together each is secured on its own. Heaters in guest and pool houses are strapped to those buildings' own walls, which may be masonry. Wider replacement tanks get new straps and flexible connectors, and the installer points out where the new lines run. Details such as bracing height and fastenings follow local requirements, which the installer confirms and notes anything unusual about the setup.
A sound heater that was never secured can be strapped as it stands, and loose straps are tightened at a service visit. In an older pool house or garage, straps sometimes run to a pipe or loose board rather than framing; those are refastened properly. Ask the installer what holds each strap, and ask to see it when the job is done.
Choosing a replacement
Start with the fuel, the space and the demand. A garage or mechanical room with room and a circuit suits a heat pump unit; an outside wall with a large enough gas line suits tankless; a guest house may need only a small electric heater. Then count the fixtures in use at the busiest hour. Programs vary; check with your utility, because details change. The installer prices the realistic options side by side, heater by heater.
Atherton ZIP code
ZIP codes served: 94027
Nearby areas with their own pages include Menlo Park, Redwood City, Palo Alto, San Carlos and Portola Valley. See every city in the Bay Area.
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Atherton water heater FAQs
Treat it promptly. A little water at the base can come from the drain valve, the relief line or condensation, which are repairable, or from the tank itself, which isn't. Dry the area and watch for more. In a basement mechanical room, a leak alarm catches it early.
It carries combustion gases from the burner to the outdoors. Older tanks use a metal flue that relies on hot exhaust rising; power-vent, sealed-combustion and tankless models use a fan and often plastic pipe. A loose, rusted or blocked vent can spill exhaust indoors, so it's checked at every service.
Soot means the burner isn't burning cleanly or exhaust isn't venting properly, which can also mean carbon monoxide. Don't try to adjust anything. If anyone feels unwell, leave the building and call 911. Otherwise call for a technician promptly and keep the area clear.
Often the best place. It's easy to reach, secure and replace, a leak crosses concrete, and there's room for a larger tank or a heat pump unit. Keep fuel, solvents and paint away from a gas burner and protect the heater from car bumpers.
Usually, though it's worth measuring. Newer tanks carry more insulation and can be wider or taller, which matters in a closet or a tight mechanical room. The installer checks the space, vent height and connections before choosing a model that fits.
When one can't keep up with the busiest hour, or when bathrooms are so far from a single heater that the wait is unreasonable. Large homes often split the load between two tanks, two tankless units or a heater per wing, and a guest or pool house usually has its own.
Almost always. Flexible gas and water connectors age with the heater, and new ones are inexpensive compared with a failure later. The installer also checks the shutoffs, relief line, vent connector and any recirculation fittings while everything is open and accessible.
When the Fair Oaks area incorporated in 1923, that name was already taken, so residents chose to honor Faxon Dean Atherton, an early landowner. The town incorporated on September 12, 1923, and its ZIP code is 94027. Share the address and we'll connect you with a pro.
Yes. We connect callers with independent water heater pros across the 94027 ZIP code, including main houses, guest houses, pool houses and staff quarters on the same property. Menlo Park and Redwood City each have their own separate pages here.