Tankless Water Heater Planning Guide in Utah County, UT
How to size a unit for January, plan for hard water, and get the permit and rebate right, from Lehi to Spanish Fork. Send a request and it goes to an independent local contractor.
Estimate the flow you need
Count the showers that might run at the same time and pick a target temperature. The inlet figure is an example; measure your own before you compare bids.
- Peak flow
- 2.5 GPM
- Temperature rise
- 75°F
- Gas input
- ≈ 99,000 BTU/h
- Electric
- ≈ 27 kW
An estimate for planning a conversation, not a unit recommendation. Ask the installer to confirm flow, venting, and gas or electrical capacity on site.
How this is calculated
- Peak flow = the sum of each fixture count × its GPM.
- Temperature rise = target temperature − inlet temperature (45°F).
- Gas input (BTU/h) ≈ flow × rise × 500 ÷ 0.95 efficiency. 500 ≈ 8.33 lb per gallon × 60 minutes per hour.
- Electric (kW) ≈ flow × rise × 500 ÷ 3,412 BTU/h per kW.
| Fixture | GPM each |
|---|---|
| Standard shower | 2.5 |
| WaterSense shower | 2 |
Faucets, dishwashers, and washing machines vary, so add their flow from the rating on the fixture or in its manual. The gas figure assumes a unit that is 95% efficient; use the rated efficiency of any unit you compare.
Figures checked October 2026.
Add this to my requestAt a glance
- water hardness Provo reports in its 2025 water report
- 10-15 gr/gal
- normal January low in Provo, NOAA 1991-2020 normals
- 23.8°F
- Enbridge Gas ThermWise rebate for an ENERGY STAR gas tankless unit
- $300
- fuel gas code edition Utah adopted effective July 1, 2026
- 2024 IFGC
Three local facts shape most tankless projects here
Size for winter. Provo's normal January low is 23.8°F, based on NOAA's 1991-2020 climate normals for the BYU weather station. Colder incoming water gives the unit more degrees to add, so it delivers less flow. To find your own number, run the cold water for a few minutes on a January morning, read it with a kitchen thermometer, and size for that reading. The gas vs. electric page walks through the math.
Plan for hard water. Provo's 2025 water report describes its water as moderately hard, at 10 to 15 grains per gallon. Orem's 2025 report lists 7 to 25 grains per gallon for its city-owned sources. The U.S. Department of Energy's tankless guide says scale can restrict flow through the heat exchanger and shorten the unit's life. Plan the softener or scale filter, the flushing valves, and the flushing schedule before the unit goes on the wall. The local conditions page shows each city's published figures.
Check your city's permit rules. Provo, Orem, Spanish Fork, Highland, Alpine, and Springville name water heaters on their own pages. Lehi, American Fork, Pleasant Grove, and Mapleton apply the residential code Utah adopted, which requires a permit to replace a gas or plumbing system. Provo also asks for a gas line diagram when the new unit is tankless.
Tank or tankless: the tradeoffs
| Question | Tank water heater | Tankless water heater |
|---|---|---|
| Hot water supply | What the tank holds, then a wait while it reheats | Continuous, up to the unit's flow at your temperature rise |
| Space | Sits on the floor | Mounts on a wall |
| Gas line | Existing line often works | DOE says the house line will need to be 3/4 inch in most cases |
| Venting | Existing vent may work | New vent, often through a side wall |
| Hard water care | Drain sediment from the tank | Flush the heat exchanger on the manufacturer's schedule |
A tankless conversion fits best when you plan to stay in the house for years, have wall space near an exterior wall for the vent, and will keep up with flushing.
Costs, rebates, and fees
Your price moves most with the gas line, the vent route, and any panel work an electric unit needs. Enbridge Gas Utah lists a $300 ThermWise rebate for an ENERGY STAR gas tankless water heater. Provo lists a $75 base fee for a standard trade permit plus a $12 processing fee.
Next steps
- Gas vs. electric: condensing, non-condensing, and electric units, with sizing math.
- Planning guides: permits by city, winter sizing, flushing, rebates, and license checks.
Wasatch Tankless is a planning resource. A request you send through the contact page goes to an independent local contractor.
Options compared
| Option | Description |
|---|---|
| Condensing gas tankless | Recovers heat from the exhaust and produces condensate that needs a drain. |
| Electric tankless | No gas line or vent, but whole-home units draw a large electric load. A 36 kW unit at 240 volts draws 150 amps, so the panel and service often need review. |
| Scale protection | A whole-house softener or an inline scale filter ahead of the unit, chosen to keep water within the manufacturer's hardness limit. |
How a tankless install usually runs
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Measure demand
The installer counts the fixtures that may run at the same time, checks the winter inlet water temperature, and looks at gas line size and possible vent routes.
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Choose a unit
Gas or electric, condensing or non-condensing, sized for the flow the home needs at its coldest inlet temperature. Compare your city's hardness figure with the manufacturer's water-quality limit.
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Apply for the permit
The contractor, or an owner doing the work, applies for the permit with the city. Provo, for example, asks for a gas line diagram with permits for tankless water heaters.
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Install and inspect
Typical work includes mounting the unit, running or upsizing the gas line, venting, adding service valves for flushing, and piping the relief valve. The city inspects the finished work.
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Flush on schedule
DOE's tankless guide puts flushing anywhere from twice a year to once every three years, depending on water quality and model. Follow the manufacturer's instructions.
What to weigh before you buy
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Size for the coldest month
A tankless unit's flow depends on how many degrees it has to heat the water. Incoming water is colder in winter, so the same unit delivers less hot water in January. Measure your winter inlet temperature, or ask the installer to, and size for it.
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Plan for hard water
Provo reports 10-15 grains per gallon of hardness and Orem's wells 7-25. The U.S. Department of Energy notes that scale restricts flow through the heat exchanger and shortens unit life, and that some manufacturers require a softener above 8-14 grains.
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Check the gas line and vent route
Gas tankless units often need a larger gas line than the tank heater they replace. DOE's tankless guide says the line in the house will need to be 3/4 inch in most cases. Condensing models also need a way to drain condensate.
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Budget for the permit and the rebate
Utah County cities require a permit to replace a water heater. Enbridge Gas Utah's ThermWise program lists a $300 rebate for an ENERGY STAR gas tankless water heater.
Planning guides
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Checking a Utah plumber's license before a water heater job
Utah's licensing law treats gas piping as plumbing and requires gas appliance certification. This guide covers the license lookup and the questions to ask before you sign.
Updated
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Hard water, scale, and flushing a tankless unit in Utah County
Provo, Orem, and American Fork all publish hard-water figures. This guide covers what scale does to a tankless unit, your treatment options, and how a flush works.
Updated
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Sizing a tankless water heater for a Utah County winter
A tankless unit delivers less hot water when the incoming water is cold. Measure your January inlet temperature, add up peak demand, and size to the coldest month.
Updated
Common questions
How hard is the water, and why does it matter for a tankless unit?
Provo's 2025 water report says 10-15 grains per gallon, Orem's wells range from 7 to 25, and American Fork suggests setting softeners to 12.38. DOE notes that scale restricts flow through the heat exchanger and shortens unit life. Rinnai's Value Series manual lists a hardness limit of 200 mg/L, about 11.7 grains. Look up your own city's annual water quality report.
How often should a tankless unit be flushed?
Follow the manufacturer's instructions. DOE's tankless guide puts flushing anywhere from twice a year to once every three years, depending on water quality. Rinnai's manual describes a flush with white vinegar, and Rinnai's terms exclude damage from scale build-up.
Are there rebates for tankless water heaters?
Enbridge Gas Utah (formerly Dominion Energy) lists a $300 ThermWise rebate for an ENERGY STAR gas tankless water heater. The application is due within six months; check Enbridge's form for the exact rule. Rocky Mountain Power's Wattsmart water-heating incentives are for heat pump water heaters, not tankless units. Provo, Lehi, Spanish Fork, and Springville run their own electric utilities, so check your bill to see which one serves you.
Can I install a tankless water heater myself?
Utah exempts owners working on their own property from contractor licensing. But Utah Code 58-55-308 requires anyone who installs or replaces a residential gas appliance to first complete gas-appliance training and certification, and that applies even to people otherwise exempt. A permit and inspection still apply. Ask your city about its owner-builder form.
How do I check an installer's license?
Ask for their Utah license number and look it up on the state's licensee search at secure.utah.gov/llv. Utah's definition of the plumbing trade includes gas piping. Wasatch Tankless does not check or vouch for any contractor's license.
Who receives my request?
An independent local contractor. Wasatch Tankless publishes planning information and passes requests along. It does not install, repair, or service water heaters.
Cities covered
- Provo
- Orem
- Lehi
- American Fork
- Spanish Fork
- Pleasant Grove
- Highland
- Alpine
- Springville
- Mapleton
Send a request
Describe your home and current water heater. The request goes to an independent local contractor, who can talk through sizing, venting, and permits with you.