A tankless heater can last about 20 years and never run out mid-shower, but only if the gas line is sized for it, the permit is pulled and the unit is descaled on Covina's very hard water. We install, repair and flush them across the city.
Call (626) 746-1970Request service
Written and fact-checked by John, editor, MBA in marketing
Updated against City, utility and state sources
A tankless water heater heats water only when a tap opens, delivers about 2 to 5 gallons per minute and lasts about 20 years, according to the Department of Energy. In Covina it needs a City plumbing permit, usually a larger gas line than the old tank used, venting to the manufacturer's specs, and regular descaling, because City water averages about 13.5 grains per gallon.
A tankless heater trades a higher install cost for endless hot water at a limited flow rate, lower standby losses and a longer life; a tank is cheaper to put in and simpler to replace.
A tankless (on-demand) heater stores no water. When a hot tap opens, a flow sensor fires a burner or element and heats water as it passes through a heat exchanger. The U.S. Department of Energy says tankless units are 8% to 34% more efficient than storage water heaters, last about 20 years and deliver hot water at about 2 to 5 gallons per minute. A storage tank lasts 10 to 15 years, according to the same DOE page.
| Factor | Tank | Tankless |
|---|---|---|
| Published install range | $600 to $2,500 (Angi, 2025) | $1,404 to $3,901 (Angi, 2026) |
| Life | 10 to 15 years | About 20 years |
| Hot water limit | Tank volume and recovery | Flow rate, about 2 to 5 gpm |
| Gas line | Usually existing | Often upsized from the meter |
| Venting | Draft hood and Type B vent through the roof | Model-specific vent, often through a side wall |
| Hard water care | Flush sediment, check anode | Descale exchanger, clean inlet screen |
If the goal is a quick swap of a failed tank, a tank is usually faster and cheaper, and our water heater repair and replacement page covers that path. If you plan to stay in the home, take long showers back to back or want the garage floor back, tankless deserves a look. The DOE notes that homes with high hot water demand may need more than one unit.
City of Covina water averaged about 13.5 grains per gallon of hardness in 2025, which the City calls very hard, so most tankless units here need descaling on a regular schedule.
The City's 2025 Consumer Confidence Report lists average hardness of 230 mg/L, with a range of 190 to 280 mg/L, roughly 11 to 16 grains per gallon. Calcium averaged 56 mg/L and magnesium 22 mg/L. The water met every state and federal standard. A tankless heat exchanger has narrow passages, and when calcium drops out as water heats, scale builds inside them. That cuts flow, makes the exchanger run hotter and triggers error codes.
Covina has six water suppliers, and their numbers differ. Check the report from the supplier on your bill.
| Supplier | Average hardness | Source |
|---|---|---|
| City of Covina Water Division | 230 mg/L, about 13.5 gpg (range 190 to 280 mg/L) | City 2025 CCR |
| Golden State Water, San Dimas system | About 205 mg/L, about 12 gpg (range about 5 to 18 gpg) | Golden State Water CCR |
| Suburban, Valencia Heights, Azusa, Glendora | See each supplier's own report | Name on your water bill |
Signs a tankless unit needs descaling now:
Turn off the unit, close the gas valve, and close the cold and hot isolation valves.
Hoses go on the service ports of the isolation valves, with a small pump in a bucket of the descaling solution the manufacturer approves.
The solution runs through the heat exchanger for the time the manual sets.
The solution is drained and the exchanger flushed with fresh water.
The cold inlet screen is cleaned, valves reopened, air bled from the lines and the unit tested at a full and a low flow.
Angi lists a water heater flush or descaling at $110 to $200. That is a published range, not a quote. Call (626) 746-1970 for an exact quote. How often depends on your supplier's hardness and how much hot water you use, and the manufacturer's manual sets the interval. A softener sized to your water cuts scale at the heater and at every fixture. See our water softeners and filtration page and the Covina water suppliers and hardness guide.
A gas tankless heater usually needs far more gas at full fire than the tank it replaces, so the gas line is checked against the unit's rated input before we quote.
About two-thirds of Covina homes were built before 1970, according to the City's Housing Element. Most of their gas piping was sized for a tank water heater, a range, a dryer and a wall or floor furnace. A tankless unit can need much more gas when it fires to full capacity. If the pipe, the meter or the regulator cannot deliver it, the unit starves. You see flame failure codes, or lukewarm water when two showers run at once.
Sizing is arithmetic, not a guess. The plumber measures the pipe length from the meter to the heater, lists every gas appliance on the system and its input, and checks the pipe size against the code sizing tables and the input on the tankless spec sheet. Sometimes the existing line is fine. Often a new, larger line runs from the meter to the heater.
| Item | What we check |
|---|---|
| Rated input | The tankless unit's maximum Btu input from the spec sheet |
| Other appliances | Range, dryer, furnace, pool heater, barbecue and fire pit on the same system |
| Pipe length and size | Developed length from the meter and existing pipe diameter against code sizing tables |
| Meter and regulator | Whether the meter set can deliver the new total load; SoCalGas handles the meter itself |
| Shutoff, flex connector, sediment trap | Approved gas shutoff, approved flex connector and a sediment trap with at least a 3-inch nipple, per Handout #12 |
| Bonding | #8 copper bonding wire tying the gas, cold and hot lines at the heater, per Handout #12 |
| Pressure test | New gas piping tested before it is covered or put into service |
Angi says a gas line upgrade for a tankless install can run up to $1,000, and HomeAdvisor lists $272 to $936 for a gas line installation. These are published ranges, not quotes. Call (626) 746-1970 for an exact quote. A long run across a lot, or a line that has to go under a driveway, moves the price. Before any trenching, 811 must be called at least two business days ahead. More on gas piping is on our gas line plumber page.
Yes, a tankless install needs a City of Covina plumbing permit, because Handout #12 requires one for all water heater replacements or new installations, and the gas line work is permitted with it.
Handout #12, effective January 1, 2026 under the 2025 California Plumbing Code, applies to every water heater in the city, tank or tankless. Permits go only to a C-36 plumbing contractor or an approved homeowner-builder. Covina has no online permit portal: the permit is pulled in person at Building & Safety, 125 E College St, phone 626-384-5460, Monday to Thursday 7 a.m. to 6 p.m., closed 1 to 2 p.m. Handout #14 says most mechanical, electrical and plumbing permits are issued over the counter while you wait, and that no work may be concealed before inspection. Inspections are requested by email.
Handout #12's roof vent rules (12 inches above the roof, 5 feet of vertical rise above a draft hood) were written around tank heaters with draft hoods. A tankless unit's vent follows its listing and the manufacturer's instructions, which the handout requires for listed appliances. Homes in unincorporated Charter Oak follow Los Angeles County rules instead. Our Covina plumbing permits guide covers the counter process in more depth.
Tankless heaters use a fan and the vent system their manufacturer specifies, not a tank's draft hood, and condensing models also need a drain for acidic condensate.
The vent material and size are whatever the manufacturer lists for that model. Many models vent straight out a side wall, so the old roof vent is no longer used. The old Type B vent is then removed or capped and the roof patched. Termination clearances from windows, doors and air intakes come from the manual, and the inspector checks them.
Condensing tankless units produce acidic condensate that needs its own drain line, and some installs call for a neutralizer that raises the pH before it reaches a drain. We follow the manual and confirm any neutralizer requirement with Building & Safety at the counter. The relief valve discharge stays separate and ends outside, as Handout #12 requires.
| Item | What we check |
|---|---|
| Vent material and size | What the manufacturer lists for that model |
| Termination | Clearances from windows, doors, air intakes and property lines per the manual |
| Old vent | Abandoned Type B vent removed or capped, roof flashing sealed |
| Condensate line | Slope, trap and an approved drain point; neutralizer where required |
| Relief discharge | Separate line to the outside, 6 to 24 inches above grade |
| Outdoor units | Rated for outdoor use, enclosure or cabinet per the municipal code, HOA approval where needed |
Tankless fits best in a home you plan to keep, with a reachable gas meter, a short vent path and a household that wants long or back-to-back showers.
About 58% of Covina homes are single-family detached, and about two-thirds of all homes were built before 1970. The garage wall usually has room for a unit, a side-wall vent and a gas line that can be upsized from the meter. Usually a good fit.
Homes on the older blocks near downtown Covina may have the heater in an outside closet with galvanized supply pipe. The gas run and the pipe condition decide the job, and sometimes repiping makes sense at the same time.
The heater may sit in an interior closet with no easy outside wall. Venting, condensate and written HOA approval decide it. We look before we quote.
Some tankless models support recirculation, which shortens the wait for hot water at a far bathroom. The unit's minimum flow rate and the loop design need to match.
Angi's published 2026 range for tankless installation is $1,404 to $3,901; these are national estimates, not quotes. Call (626) 746-1970 for an exact quote.
| Item | Published range |
|---|---|
| Tankless installation, overall | $1,404 to $3,901 |
| Gas unit, 120,000 to 140,000 Btu | $500 to $1,200 |
| Gas unit, 180,000 to 200,000 Btu | $900 to $2,200 |
| Labor | $600 to $1,850 |
| Gas line upgrade | Up to $1,000 |
| Electrical upgrade | $200 to $400 |
| Vent termination kit | $40 to $100 |
| Permit | $50 to $100 |
| Flush or descaling | $110 to $200 |
The biggest swings on a Covina tankless job come from the gas line run from the meter, the vent route, where condensate goes, and removing the old tank's stand and roof vent. Handout #12 items such as bonding, insulation and an enclosure can add to it. You get a written price before work starts. Call (626) 746-1970 for an exact quote. More published ranges are in our plumbing costs in Covina guide.
Most tankless service calls in Covina come down to scale, gas supply, venting or a dirty inlet screen, and most are repairable.
| Symptom | Likely cause |
|---|---|
| Hot then cold bursts | Scale in the exchanger, flow below the unit's minimum, crossed plumbing |
| Ignition or flame failure code | Undersized gas line, low gas pressure, closed gas valve |
| Unit will not start at a low-flow faucet | Flow below the activation rate, clogged aerator or inlet screen |
| Water dripping from the cabinet | Blocked condensate line, leaking fitting, failed exchanger |
| Exhaust smell or vent error | Vent blocked, disconnected or ending too close to an opening |
| Relief valve discharging | High pressure or thermal expansion |
| Scale or service code | Due for descaling on hard water |
Angi lists tankless repair at $100 to $1,300 (2025 data). That is a published range, not a quote. Call (626) 746-1970 for an exact quote. Many repairs start with a descale and an inlet screen cleaning, which often clears the code on its own.
A real person answers 24 hours a day. You get an honest arrival window and a written price before any work starts.
Often, if you plan to stay. The Department of Energy says tankless units are 8% to 34% more efficient than tanks and last about 20 years versus 10 to 15. The tradeoffs are a higher install cost, often a bigger gas line and regular descaling on Covina's very hard water.
Follow the manufacturer's interval and lean toward the shorter end. City of Covina water averaged about 13.5 grains per gallon in 2025, which the City calls very hard. Swinging temperatures, lower flow or a scale code mean it is due now.
Often, yes. A gas tankless unit can need much more gas at full fire than a tank. The plumber checks pipe size, length from the meter and the other appliances against the unit's rated input. Angi says a gas line upgrade can run up to $1,000. Call (626) 746-1970 for an exact quote.
Yes. Covina's Handout #12 requires a plumbing permit for all water heater replacements and new installations, tankless included. It is pulled in person at Building & Safety in City Hall, usually over the counter, and inspections are requested by email.
Usually, if the model is rated for outdoor use. Handout #12 calls for water heaters to be enclosed or in an approved cabinet per the municipal code, and HOA properties need written approval for exterior work. Vent clearances come from the manufacturer's manual.
Condensing models do. They produce acidic condensate that needs its own drain line, and some installs call for a neutralizer. The relief valve discharge must stay separate and end outside, 6 to 24 inches above grade, as Handout #12 requires.
Yes, on hard water. A softener sized to your supplier's tested hardness cuts the scale that builds in the heat exchanger, so descaling is needed less often. Check your supplier's report first, since Covina's six suppliers report different numbers.
Angi publishes a national range of $1,404 to $3,901 for tankless installation, based on 2026 data. Gas line upgrades, venting and condensate work move the price. That is a published range, not a quote. Call (626) 746-1970 for an exact quote.
Facts on this page come from these public sources, checked November 1, 2026.