Key takeaways
- Tankless water maintenance helps prevent mineral buildup, maintain heating efficiency, and extend your water heater’s lifespan through regular flushing and inspections.
- Flush and descale your tankless water heater annually, or more frequently in Southern California’s hard-water areas, depending on manufacturer recommendations.
- Riverside Public Utilities reported an average water hardness of 197 mg/L (approximately 12 grains per gallon) in 2025, highlighting the importance of regular descaling.
- Homeowners can clean inlet filters and inspect accessible vents, but gas connections, combustion components, and safety controls require professional servicing.
- ENERGY STAR estimates whole-house gas tankless water heaters can last 20 years, making regular maintenance important for protecting your investment and ensuring reliable hot water.
That chalky white ring around your showerhead or faucet is more than a surface stain. The same minerals in Southern California’s hard water can build up inside your tankless water heater, coating the hidden heat exchanger and affecting performance.
Tankless water heaters require relatively little maintenance, but regular upkeep is essential. A yearly tankless water maintenance routine helps control mineral buildup, maintain efficiency, and extend your unit’s lifespan.
This guide covers essential maintenance tasks, recommended schedules, DIY cleaning steps, and when to call a professional.
What does tankless water heater maintenance include?
Tankless water heater maintenance includes flushing and descaling the heat exchanger, cleaning the inlet water filter, checking air intake and vent openings, inspecting condensate components, and checking burners and safety controls. Most of these tasks should be performed annually, although homes with hard water may require more frequent descaling.
The table below breaks down each maintenance task, why it matters, how often it should be performed, and whether you can handle it yourself or need professional assistance.
| Key Maintenance Task | Purpose and Benefits | Recommended Timeline | DIY or Professional Service? |
|---|---|---|---|
| Clean the inlet water filter | Removes trapped debris that can restrict water flow and trigger error codes. | During every flush or more often if sediment is present. | Homeowner |
| Flush and descale the heat exchanger | Removes mineral buildup that restricts water flow and reduces heat transfer efficiency. | Annually, or approximately every six months in hard-water areas, depending on manufacturer guidance. | Homeowner if the manual permits and isolation valves are installed; professional recommended. |
| Clean the air intake screen and check vent terminations | Helps maintain proper airflow and supports safe combustion. | Annually, or more frequently for outdoor units. | Homeowner for visual checks; professional for venting repairs. |
| Inspect the condensate trap and neutralizer (condensing models) | Helps ensure acidic condensate drains properly and is neutralized when required. | Annually | Licensed professional |
| Check the burner, flame sensor, and igniter; test the pressure relief valve | Identifies soot buildup, wear, corrosion, and potential safety issues. | Annually | Licensed professional |
Note: Always refer to your owner’s manual before performing maintenance, as specific procedures, safety requirements, and service intervals vary by manufacturer and model.
Why does hard water make tankless maintenance more important in Southern California?
Hard water contains dissolved calcium and magnesium that can form mineral scale when heated. Since the water in a tankless heater passes through relatively narrow heat-exchanger passages, deposits can occur in these spaces, resulting in restricted flow and reduced heating efficiency.
To help you understand how your location affects scale buildup, here’s an overview of water hardness across Southern California.
- Riverside County: Riverside Public Utilities’ 2025 Water Quality Report states an average hardness of 197 mg/L, or approximately 12 grains per gallon. This figure is applicable to the utility’s reported supply, and it should not be treated as a measurement for every Riverside County home.
- Los Angeles County: The LADWP 2025 Drinking Water Quality Report provides information on drinking water sources and quality. Hardness can vary depending on the local service area and its mix of Colorado River water, State Water Project water, and groundwater.
- Orange and San Bernardino counties: Water hardness varies city by city; homeowners should consult their local utility’s annual Consumer Confidence Report (CCR) to check exact local mineral measurements.
How can you find out how hard your water is?
To determine your water’s hardness, check your municipal utility’s annual Consumer Confidence Report, use inexpensive home test strips, or have your water tested during a routine service visit.
A properly installed water softener or scale-prevention system may reduce mineral buildup and extend the time between flushes. However, doing so won’t completely eliminate the need for maintenance. Service Champions also installs water filtration systems and water softeners for homeowners looking to improve water quality at the source.
How do you flush and descale a tankless water heater, step by step?
These steps apply to most gas tankless water heaters with isolation (service) valves. If your unit doesn’t have these valves, stop here and contact a licensed professional to have them installed before attempting a flush.
What you’ll need
Before starting the flushing process, gather the following tools and supplies to clean your tankless water heater:
- Small submersible pump
- Two washing-machine-style hoses
- Five-gallon bucket
- Manufacturer-approved descaling solution (some models allow food-grade white vinegar)
- Adjustable wrench
- Clean towels and rubber gloves
The steps
Once you have the necessary supplies, follow these steps to flush and descale your tankless water heater. Check your owner’s manual for model-specific instructions before starting.
Step 1: Turn off the power. Switch off the water heater and close the gas supply valve.
Step 2: Close the isolation valves. Shut the hot and cold water isolation valves to stop water from entering the unit.
Step 3: Connect the hoses. Remove the purge port caps and connect one hose from the pump to the cold-side port and another from the hot-side port into the bucket.
Step 4: Circulate the descaling solution. Fill the bucket with the approved solution, open the purge valves, and run the pump for the time specified in your owner’s manual.
Step 5: Rinse the system. Drain the descaling solution, refill the bucket with clean water, and rinse the system according to the manufacturer’s instructions.
Step 6: Clean the inlet water filter. Remove the filter, rinse away any trapped debris, and reinstall it securely.
Step 7: Reconnect the system. Close the purge valves, disconnect the hoses, replace the caps, and reopen the hot and cold isolation valves.
Step 8: Restore power and check for leaks. Restore the gas and power supplies, run a hot-water tap until the flow is steady, and inspect all fittings for drips.
Safety precautions
If you smell gas at any point, leave the house immediately and call your gas utility from outside. Do not attempt to restart the water heater or operate electrical switches.
Damage caused during DIY maintenance may affect your warranty coverage. Check the warranty terms and maintenance instructions in your owner’s manual before starting. If you’re unsure about any connection or restart procedure, have a licensed professional handle the work.
How often should you flush a tankless water heater?
Once a year is a common starting point for flushing a tankless water heater, but homes with hard water may need more frequent descaling. The ideal maintenance interval depends on water hardness, manufacturer recommendations, household water usage, and any installed water-treatment system.
The table below outlines the suggested flushing intervals for different water conditions and household needs to help you plan your maintenance schedule.
| Your situation | Suggested flush interval |
|---|---|
| Soft to moderately hard water, typical household | Once a year |
| Hard water (for example, Riverside’s reported 12 grains per gallon) | More often than once a year, per your manual |
| Large household or heavy simultaneous use | More frequent inspections between flushes |
| Water softener or scale-prevention system installed | Follow the manual; flushes are usually needed less often |
Scheduling a flush in the fall can help prepare your water heater for increased hot water use during winter and reduce the risk of unexpected breakdowns. Always follow your manufacturer’s recommended maintenance intervals.
Should you service a tankless water heater yourself or hire a pro?
Filter cleaning and visual checks can be done by homeowners on their own, but gas, combustion, sensor, and venting work should be left to a licensed pro. Homeowners can perform routine maintenance between professional visits but should hire a technician for tasks requiring specialized tools or expertise.
| DIY-friendly Tasks | Call a Licensed Professional |
|---|---|
| Inspect the exterior for any visible damage | Diagnose burner, ignition, and combustion problems |
| Check that accessible air intake openings are clear | Repair gas lines or broken venting |
| Clean the inlet water filter if the manual permits | Inspect internal sensors and sealed parts |
| Record error codes and consult the manual | Inspect safety controls and the pressure relief valve |
| Flush the unit if the manual allows DIY servicing and suitable valves are installed | Handle complex descaling, condensate repairs, and work beyond the manual’s homeowner instructions |
During a professional tankless water heater service visit, Service Champions technicians perform a thorough system inspection backed by the company’s service guarantees:
- Repair work performed by licensed plumbers (CSLB #799170).
- An upfront price agreed before any work starts, backed by the No Change Order Guarantee: the price quoted is the price paid.
- The Better Than We Found It Guarantee: the home is left cleaner than it was found, or Service Champions pays for a cleaning service.
Homeowners can also check CHAMP-Rewards to learn about maintenance membership benefits and available scheduling options.
What other tankless water heater cleaning should you do between flushes?
Between annual servicing appointments, a few simple checks can help keep your tankless water heater running properly and catch potential problems early.
Here are four maintenance tasks you can perform between flushes to prevent buildup, maintain proper airflow, and identify signs of trouble.
1. Rinse the inlet water filter
The cold water inlet filter screen can collect silt, pipe rust, and fine debris. Rinsing the filter with clean tap water every few months, following your manufacturer’s instructions, helps prevent restricted water flow and error codes.
2. Keep the air intake and vent terminations clean
Gas tankless units need uninterrupted airflow for safe combustion. Check accessible air intake openings and the area around exterior vent terminations for dust, leaves, and cobwebs. For outdoor units in the Inland Empire, wind-blown dust and debris can accumulate around these openings. Leave internal vent cleaning and repairs to a professional.
3. Check the condensate line on condensing models
High-efficiency condensing units produce acidic condensate during operation. Periodically check the condensate line for visible leaks, blockages, or drainage problems. Have a professional inspect or replace clogged neutralizer cartridges.
4. Check for recurring error codes
If an error code appears on your water heater’s digital controller, write it down and check your owner’s manual instead of repeatedly resetting the unit. Recurring error codes may indicate an internal problem that requires professional servicing.
What signs mean your tankless water heater needs professional servicing?
Fluctuating water temperatures, weak water flow, long waits for hot water, and recurring error codes are common signs of mineral buildup or a malfunctioning component.
Look out for the following warning signs:
- Temperature fluctuation during showers (the “cold water sandwich” effect)
- Reduced water flow or pressure at hot taps
- Slow heating and long waiting times for hot water
- Repeating error codes on the display panel
- Popping, clicking, or unusual noises during operation
- Moisture, condensation, or drips around the unit
- Visible corrosion or rust on fittings and vent lines
- An unexplained increase in monthly gas bills
This information can help the plumber determine the exact cause of the problem. A professional cleaning or targeted repair may resolve the issue without requiring a replacement.
How long does a tankless water heater last, and when should you replace it?
According to ENERGY STAR, a tankless gas water heater for a whole house has a lifespan of 20 years. This is significantly longer than a conventional tank model, and regular descaling is the best way to ensure the unit lasts that long.
Should you repair or replace an aging tankless water heater?
The decision to repair or replace an aging tankless water heater depends on its age, condition, repair costs, and ability to meet your household’s hot water needs.
The table below compares common signs that indicate your tankless water heater may only need repairs versus situations where replacing the unit may be the better option.
| Repair Indications | Replacement Indications |
|---|---|
| Unit is under 10–12 years old | Leaking or severely corroded heat exchanger |
| Issue is isolated to a single replaceable part (e.g., sensor, valve) | Repeated system failures and costly breakdowns |
| Replacement parts are readily available | Obsolete unit with discontinued parts |
| Unit size matches your household’s current demand | Unit can’t keep up with household demand, or you need to replace water heater equipment |
Is a tankless water heater worth it over a traditional tank in Los Angeles?
Tankless water heaters are a good option for Los Angeles families planning to stay in their homes for a long time. They offer a longer lifespan, can reduce gas consumption, and save space. However, homeowners should budget for regular descaling due to LA’s hard water.
The table below compares tankless and traditional tank water heaters based on hot water supply, lifespan, operating costs, maintenance requirements, and installation considerations to help you decide which option best suits your home.
| Feature | Tankless Water Heater | Traditional Tank Water Heater |
|---|---|---|
| Hot Water Supply | Continuous, on-demand hot water | Limited to storage tank capacity |
| Expected Lifespan | Up to 20 years | 10 to 15 years |
| Operating Cost | Lower (ENERGY STAR estimates certified gas models save ~$95/year for a family of 4) | Higher (heats stored water continuously 24/7) |
| Space Required | Wall-mounted, compact footprint | Requires dedicated floor space |
| Upkeep in Hard Water | Needs periodic descaling and flushing | Needs periodic tank flushing and anode rod checks |
| Installation Considerations | May require gas line or venting upgrades | Uses standard existing utility connections |
If you’re considering your options, be sure to check out our comprehensive buyer’s guide before making a decision. Older homes in LA County cities such as Pasadena, Alhambra, and Arcadia may require gas line or venting upgrades. Therefore, it’s important to schedule a home inspection before finalizing the installation cost.
Where can you get a tankless water heater quote in San Bernardino County?
Service Champions offers tankless water heater quotes and installation in San Bernardino County from its Colton office (600 E Valley Blvd, Colton, CA 92324). It serves cities such as Chino, Chino Hills, Montclair, Ontario, Rancho Cucamonga, and Upland. Each quote is an upfront price that the homeowner agrees to before the work begins.
Our comprehensive home inspection covers your household’s peak hot water demand, existing gas line capacity, venting requirements, and water quality. Every installation comes with industry-leading service guarantees, including:
- Happy Money Promise: 100% satisfaction with new equipment in the first year, up to removal and a refund.
- Highest Value Guarantee: If the homeowner finds a lower published price (comparable) for the same installation, Service Champions offers the difference plus a $50 bonus.
- Lifetime Installation Guarantee: Free return service for problems caused by the original installation for as long as the homeowner owns the system.
Many homes in the Inland Empire have outdoor tankless water heaters that are exposed to intense summer heat and accumulating dust. Our technicians ensure installations are suited to local weather conditions and also offer annual descaling services. Book your professional tankless water heater installation with our local team.
Make tankless water maintenance a yearly habit with Service Champions
Protecting your tankless water heater is easiest when you tie it to a date you already remember, like the clock time change in the fall or the start of a new school year. Scheduling an annual flush as part of your seasonal maintenance routine helps prevent unnoticed mineral scale buildup.
Proper maintenance helps protect your investment, maintain energy efficiency, and provide a reliable hot water supply year after year.
With Service Champions, you can expect to have:
- Upfront Pricing: Know the price before any work begins.
- Professional Servicing: Get help with flushing and removing mineral buildup.
- Reliable Hot Water: Keep your system maintained for smooth and consistent performance.
Book a tankless water heater flush with Service Champions and get an upfront price before any work begins. Give us a call at (714) 439-9648 and set up your appointment now!
Call (714) 439-9648 Book OnlineFrequently Asked Questions About Tankless Water Heater Maintenance
1. Do electric tankless water heaters need the same maintenance as gas models?
Yes. Electric tankless water heaters need regular descaling to eliminate mineral scale from heating elements; they do not require burner or gas venting maintenance, though.
2. Does skipping yearly maintenance affect a tankless water heater’s warranty?
Yes. Most manufacturers require a written record of annual descaling. Failure to remove this plaque and causing damage could void your warranty.
3. How much does a professional tankless water heater flush cost in Southern California?
A professional tankless water heater flush typically costs between $150 and $350 in Southern California. However, the exact price depends on the unit’s accessibility, water hardness, and whether isolation valves need to be installed.
4. Does a recirculation pump change how often a tankless water heater needs flushing?
Yes, because the recirculation pump persistently passes hot water through the heat exchanger, causing mineral scale to accumulate even faster and requiring flushing as often as every six months.
5. Do tankless water heaters need freeze protection in Southern California?
While this may be less common in coastal areas, in the hilly and mountainous regions of the Inland Empire, outdoor tankless units must have built-in freeze protection heaters or pipe insulation to prevent winter freeze damage.
