What Does a Tankless Water Heater Cost in Downey, CA?

A tank-to-tankless conversion in Downey has a book price: $3,295 to replace a 40-gallon tank with a Noritz EZTR40, or $3,695 to replace a 50-gallon tank with an EZTR50, installed. We can publish those two numbers because the EZTR models connect to the hookups a storage tank already has; every other tankless unit needs its own gas line sizing and venting, so it is quoted on site. This guide covers what is in the price, what is not, and the Downey-specific pieces: the permit and the water.

The conversion price covers removing the storage tank, installing the Noritz EZTR40 or EZTR50 on the existing hookups, new hot and cold water supply lines, a new gas supply line, and isolation valves so the unit can be flushed without shutting the house down. Hauling the old tank away is $95. A drain pan is $75 and a gas sediment trap is $225 where the inspector calls for them. The permit is separate and is covered below. The full book is on our pricing page.

Every tankless brand other than the Noritz EZTR line needs its own gas line sizing, venting and mounting, and that is decided by the house, not the catalog: how far the gas run is, what size the line is, where the vent can exit, and whether the unit is moving. So a Navien, Rinnai, Takagi or Rheem installation is evaluated on site and quoted in writing before any work starts. A venting upgrade from single wall to double wall is $250 to $450 on a tank job and is one of the items we check on a conversion. Relocating the heater, or putting one in a home that never had one, is quoted the same way. If you are weighing a tank against tankless, the tank replacement price is on our installation page and in what a water heater replacement costs in Downey.

The City of Downey Building & Safety Division requires a plumbing permit and an inspection for a water heater replacement; the office is at 11111 Brookshire Avenue and can be reached at (562) 904-7142. We pull the permit and meet the inspector for a $295 administrative fee plus the city's own permit fee, which is passed through at cost as its own line on the quote. Downey's published fee for a water heater change-out is $129.16 (the schedule's plumbing permit minimum; the water heater and vent line itself is $62 plus a $60.01 issuance fee), so the permit line comes to $295 + $129.16 = $424.16. A water heater change-out can be issued online as an auto-issue permit through the city's Accela portal. Downey's 2026 residential code amendment (Ordinance 26-1537) requires mechanical and plumbing equipment to be anchored to the structure, which for a full water heater means seismic strapping. You can decline and pull the permit yourself, but if the inspector then calls for a code correction, that work is charged at book price.

Downey sits over the Central Basin, and its groundwater runs hard; we can tell you the utility's published hardness figure for your address when we quote. A tankless heat exchanger has narrow passages, and at that hardness the manufacturers call for a descale flush every year; skipping it is how a tankless unit ends up throwing error codes a few years in. The yearly descale is $259, or it is included in the $199 per year tankless membership along with free diagnostics when a repair is needed. If the unit does fault, the tankless diagnostic is $299, includes the flush, and is waived if we repair or replace it.

Downey is known for its mid-century housing stock, the 1950s and '60s homes of North Downey, Downtown Downey and the neighborhoods east of the 605. Many garage and closet installations still have original galvanized supply lines, undersized gas connections, and no expansion tank or seismic strapping, none of which passes a current City of Downey inspection. A tankless unit hangs on the wall where the tank stood and reuses the tank's flue path when it is a Noritz EZTR on a straight swap, which is what keeps the conversion at book price. A venting upgrade from single wall to double wall is $250 to $450 where the inspector calls for it, a gas sediment trap is $225, and a drain pan is $75. A closet installation inside the house, or a second-floor unit, carries a $249 surcharge over the book price; moving the unit somewhere else is quoted on site.

Book prices apply during normal business hours, Monday through Friday, 8 AM to 5 PM; pricing outside those hours or in an emergency is subject to change. Book at least 24 hours in advance. Prices are current as of September 2026 and subject to change; nothing goes on the invoice that was not on the written quote. Financing is available on conversions. Our trucks come from Pico Rivera, about 10–15 minutes from most Downey addresses. Call 833-927-3356 or request a quote and we will confirm the number in writing.