A tankless water heater can work in most Rialto homes, but first find out who supplies your water, because three different retailers serve the city. Gas line capacity and the vent route decide the rest. Call the number on this page to be connected with a local plumber in Rialto.

Who supplies my water, and why does it matter for tankless?
Rialto has three water retailers, so the answer depends on your address. According to the City's drought planning application to the U.S. Bureau of Reclamation, the city is served by the City itself through Rialto Water Services, by West Valley Water District and by Fontana Water Company. Your bill shows which one you have. The City system relies mainly on groundwater from wells in five adjudicated basins, plus water from San Bernardino Valley Municipal Water District's Baseline Feeder and surface water from the east side of the San Gabriel Mountains.
It matters because each retailer publishes its own water quality report, and hardness is what wears down a tankless heat exchanger. Your provider's annual report lists the hardness, so read it or have the plumber test a sample. Groundwater-heavy supplies in this part of the valley tend to be on the hard side, which points toward yearly flushing and possibly a softener.
Can my current gas line feed a tankless unit?
Maybe not. A whole-house gas tankless heater can draw several times the gas of a storage tank at full fire. The plumber adds up every gas appliance in the house, measures the pipe from the SoCalGas meter and checks the length of the run. If the existing line is too small, it is enlarged or a new branch is run to the heater. The vent is the other piece: tankless units cannot share a furnace flue and need their own sealed vent through a wall or the roof. Condensing models also need a drain for their acidic condensate, usually through a small neutralizer.
Who issues the permit in Rialto?
The City of Rialto Community Development Building & Safety Division, at 150 S Palm Avenue, 909-820-2505. Permits can be applied for online through the City's Tyler EnerGov portal. A tankless conversion touches gas, venting and water piping, so plan on a permit and an inspection; the installing plumber usually handles both.
A Rialto safety note
If you smell gas near the heater, leave the house right away. Once outside, call 911 and SoCalGas at 1-800-427-2200.
Tankless Water Heaters questions in Rialto
How do I find out how hard my water is?
Will my gas line need to be upsized for a tankless unit?
Do I need a permit to switch to a tankless water heater?
Why do I get a burst of cold water in the middle of a hot shower?
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