Tankless Water Heater in San Marcos, CA

Vallecitos Water District supplies water and sewer service to San Marcos, along with parts of Carlsbad, Escondido, Vista and unincorporated areas. Its water is imported through the San Diego County Water Authority, plus desalinated seawater from the Carlsbad Desalination Plant, and it's disinfected with chloramines. With a younger housing stock than most of the county, the typical San Marcos heater sits in a garage near an exterior wall, which keeps vent runs short.

What to do now

1. Check your water pressure. Vallecitos installs a regulator on its side of the meter only where pressure exceeds 175 psi, and the district says that device doesn't protect the customer's line. If your home lacks a working pressure regulator on the house side, ask the plumber to test pressure before the new heater goes in.
2. Measure peak demand. Count the fixtures that run at the same time on a busy morning; that number sizes the unit.
3. Look at the gas line. Builder lines from the 1990s were sized for a tank. The plumber confirms the pipe from the SDG&E meter can feed a tankless burner.
4. Plan the permit. The City of San Marcos Building Division, (760) 744-1050, issues residential permits. Its packet includes a water-conserving fixture certificate: homes built on or before January 1, 1994 must replace non-compliant toilets, showerheads and faucets.
5. Add service valves. Isolation valves let the heat exchanger be flushed each year.

Signs and likely causes

Cost factors

Gas pipe sizing, the vent route, a customer-side pressure regulator if one is needed, and the unit's flow rating drive most of the price. Fixture upgrades required by the city's permit packet in older homes add their own cost. Vallecitos notes that lines serving private property are the owner's responsibility. For water problems on the district side, call Vallecitos at 760-744-0460. If you smell gas, leave the house first, then call 911 and SDG&E at 1-800-611-7343.