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Descaling tankless heater: 15 best tips to avoid scale buildup

descaling tankless heater

Tankless water heaters have become increasingly popular for their energy efficiency and on-demand hot water capabilities. These devices provide hot water without the need for a storage tank, which means they are compact and can save you money on your energy bills. However, like any other appliance, tankless heaters require regular maintenance to ensure they function at their best. Descaling tankless heater is a critical part of this maintenance process, and in this article, we will explore various factors related to descaling tankless heaters in Bend.

Factors to Consider When Descaling Tankless Heaters

Frequency of Descaling

  • Descaling tankless heaters should be performed on a regular basis to prevent mineral buildup. The frequency of descaling depends on the hardness of your water supply. If you have very hard water, you may need to descale your heater more frequently, possibly every six months. In areas with relatively soft water, annual descaling may suffice.

Water Hardness

  • The hardness of your water supply significantly impacts the rate at which mineral deposits accumulate in your tankless water heater. Water hardness is typically measured in grains per gallon (GPG) or parts per million (ppm) of dissolved minerals. The higher the hardness level, the more frequent descaling will be required.

Temperature Variations

  • Frequent adjustments to the temperature settings on your tankless water heater can contribute to scale buildup. Sudden temperature changes can cause minerals to precipitate and adhere to the heating elements.

Signs of Scaling

  • It’s essential to be vigilant and look for signs that your tankless heater needs descaling. These signs may include reduced water flow, fluctuating water temperature, and strange noises coming from the unit. If you notice any of these symptoms, it’s a clear indication that mineral deposits have built up and descaling is necessary.

Type of Descaling Agent

  • When descaling your tankless heater, you’ll need a descaling agent to break down and remove mineral deposits. Common descaling agents include white vinegar, citric acid, and commercial descaling solutions. The choice of descaling agent depends on personal preference and availability.

DIY vs. Professional Service

  • Descaling tankless heaters can be done by yourself using our guide on how to descale tankless water heaters. However, some homeowners prefer to hire a professional for this task, especially if they are not confident in their plumbing skills. Hiring a professional ensures that the job is done correctly, and it can save you time and effort.

Tips for Preventing Scale Buildup

Preventing scale buildup in tankless water heaters is not only about addressing the root causes but also about implementing practical and effective preventive measures. Here, we will explore in more detail the tips and strategies you can employ to keep your tankless heater free from scale and ensure it operates efficiently:

Install a Water Softener

  • One of the most effective long-term solutions for preventing scale buildup in your tankless water heater is the installation of a water softener. Water softeners are designed to reduce the hardness of your water supply by removing the calcium and magnesium ions responsible for scale formation. The softened water that flows into your tankless heater significantly reduces the risk of mineral deposits accumulating within the unit. While the initial investment in a water softener may seem substantial, the long-term benefits, including extended appliance lifespan and lower maintenance costs, make it a worthwhile choice.

Set the Right Temperature

  • Avoid frequent adjustments to the temperature settings on your tankless water heater. Setting the desired temperature and leaving it at a consistent level not only ensures a stable hot water supply but also prevents mineral precipitation caused by sudden temperature changes. Consistency in temperature reduces the likelihood of minerals precipitating and forming scale on the heating elements.

Flush Your Tankless Heater Regularly

  • Regular flushing of your tankless heater is an essential preventive measure that helps remove loose mineral deposits and prevents them from adhering to the heating elements and the heat exchanger. Flushing the unit at least once a year is recommended to maintain its efficiency. Flushing involves connecting a hose to the unit’s drain valve and allowing water to flow out, carrying away any accumulated debris and minerals.

Use Descaling Agents

  • In addition to regular flushing, it’s advisable to use descaling agents periodically. Descaling agents are specifically designed to dissolve existing scale deposits within the tankless heater. They work by breaking down the mineral buildup and making it easier to flush out of the unit. Popular descaling agents include white vinegar, citric acid, and commercial descaling solutions. These agents can be a valuable part of your preventive maintenance routine.

Monitor Water Quality

  • Periodically testing the hardness of your water supply can help you gauge the effectiveness of your preventive measures. Water testing kits are readily available at hardware stores and provide an easy way to determine the hardness of your water. By staying informed about the condition of your water, you can make adjustments to your preventive strategies as needed.

Perform Routine Maintenance

  • Routine maintenance is an integral part of preventing scale buildup in your tankless water heater. In addition to descaling, tasks such as checking for leaks, inspecting the burner or heating element, and cleaning the air intake and exhaust vents should be performed regularly. Routine maintenance helps identify and address issues early, reducing the likelihood of scale formation and other problems.

Consider a Whole-House Filtration System

  • Installing a whole-house water filtration system can be an effective way to reduce the mineral content in your water supply before it enters your tankless heater. Filtration systems are designed to trap impurities, including minerals, ensuring that cleaner and less mineral-rich water flows into your appliance. These systems are particularly beneficial in areas with exceptionally hard water.

Consult a Professional

  • If you are unsure about how to maintain or descale your tankless water heater, it’s advisable to consult a professional. Licensed and experienced plumbers have the expertise to handle the maintenance and descaling process, ensuring that your unit operates efficiently and remains free from scale buildup. Professionals can also provide recommendations and guidance on the best preventive measures for your specific situation.

Use Sediment Filters

  • In addition to a water softener, consider installing sediment filters in your plumbing system. These filters are designed to trap small particles and debris, preventing them from entering your tankless water heater and potentially causing scale buildup. Sediment filters can complement your preventive measures by ensuring that the water entering your appliance is as clean as possible.

Regularly Inspect and Clean Inlet Screens

  • Tankless water heaters have inlet screens that filter the water before it enters the unit. These screens can become clogged with debris and minerals over time. It’s important to regularly inspect and clean these screens to maintain optimal water flow. Clogged inlet screens can restrict water flow, leading to inefficiency and a higher risk of scale buildup.

Check for Leaks

  • A leaking tankless water heater can lead to scale buildup as water infiltrates the unit. Regularly inspect your unit for leaks and address them promptly to prevent scale-related issues. By keeping your unit watertight, you reduce the opportunity for minerals to enter and contribute to scale formation.
descaling tankless heater

Educate Yourself on Local Water Hardness

  • Water hardness varies from one location to another. To tailor your preventive measures effectively, it’s beneficial to understand the hardness of your local water supply. Local utilities may provide information on water hardness, and you can also use water testing kits to determine the specific characteristics of your water. This knowledge helps you select the most appropriate preventive strategies for your particular situation.

Invest in High-Quality Appliances

  • When installing a new tankless water heater or replacing an existing one, consider investing in high-quality appliances that are designed to resist scale buildup. Some manufacturers offer models with advanced features for scale prevention, including self-cleaning mechanisms and advanced heat exchanger materials. These features can reduce the risk of scale formation and prolong the lifespan of your unit.

Educate Family Members

  • It’s essential that all members of your household are aware of the importance of preventing scale buildup in the tankless water heater. Encourage family members to avoid frequent temperature adjustments and be mindful of water usage. By creating awareness and cooperation within your household, you can minimize the factors that contribute to scale formation.

Keep Records

  • Maintaining a comprehensive maintenance log can be a valuable tool for tracking all maintenance activities related to your tankless water heater. This log should include the date and details of maintenance tasks, such as flushing, descaling, and other preventive measures. By keeping records, you can monitor when these tasks were last performed and ensure that they are conducted in a timely and consistent manner.

Benefits of Preventing Scale Buildup

Extended Lifespan

  • Preventing scale buildup in your tankless water heater can significantly extend its lifespan. Scale deposits can cause the unit to overheat and ultimately lead to premature failure. By keeping your heater scale-free, you’ll save money on replacements.

Energy Efficiency

  • A tankless water heater that is free from scale operates more efficiently. Scale acts as an insulating barrier, reducing the heater’s ability to transfer heat. Without scale, your unit can heat water more quickly and with less energy consumption.

Consistent Hot Water Supply

  • Preventing scale buildup ensures that your tankless heater can consistently deliver hot water at the desired temperature. You won’t experience fluctuations in water temperature caused by scaling.

Reduced Maintenance Costs

  • Regular preventive measures reduce the need for descaling tankless heaters and other costly maintenance tasks. By investing in prevention, you can save money on repairs and keep your tankless heater in top condition.

Environmentally Friendly

  • An efficiently operating tankless water heater consumes less energy, which is not only cost-effective but also more environmentally friendly. Reducing energy consumption helps lower your carbon footprint.

Factors Indicating the Need for a Technician

  • Inadequate Hot Water Flow: If you notice a significant reduction in the hot water flow from your tankless water heater, it could be a sign of severe scaling. A technician can assess the extent of the scaling and determine the appropriate descaling method.
  • Fluctuating Water Temperature: Inconsistent water temperature, with the water sometimes becoming scalding hot and at other times turning cold, may indicate a problem with your tankless heater. Scaling can disrupt the heat exchanger’s efficiency, causing these fluctuations.
  • Unusual Noises: Strange noises coming from your tankless water heater, such as popping or gurgling sounds, can be a sign of scaling. If the noises persist after flushing or using a descaling agent, professional intervention is necessary.
  • Reduced Efficiency: A noticeable increase in energy consumption without an equivalent rise in hot water production can be attributed to scaling. Technicians can diagnose the issue and perform a thorough descaling to restore efficiency.
  • Frequent Error Codes: Tankless water heaters often have diagnostic features that display error codes in case of malfunctions. Frequent error codes related to heating or water flow may indicate scale-related issues.
  • Advanced Scaling: If you’ve neglected descaling for an extended period, and the scaling has advanced to a severe stage, it may require professional attention. Advanced scaling is challenging to remove with DIY methods and may result in further damage if not addressed by a technician.
  • Inconsistent Water Quality: If your water source experiences significant changes in water quality, such as fluctuations in water hardness, it can contribute to rapid scaling. In such cases, it’s recommended to have a technician assess the situation and determine the most suitable descaling approach.
  • Unit Age and Warranty: Consider the age of your tankless water heater and whether it’s still under warranty. If the unit is relatively new and covered by a warranty, having a professional technician perform descaling ensures that you don’t void the warranty by attempting DIY methods.
  • Lack of Experience or Tools: If you’re unfamiliar with the descaling process or lack the necessary tools and equipment, it’s safer and more efficient to hire a qualified technician. Einstein Plumbing technicians in Bend, Oregon are trained and have a great track record. Proper descaling requires specific knowledge and experience to avoid damaging the unit.
  • Complex Installation: Tankless water heaters come in various models, and some may have intricate installation setups. If your unit has a complex installation, it’s advisable to have a technician descale it to avoid disassembling and reassembling components incorrectly.
  • Gas-Powered Heaters: Gas-powered tankless water heaters pose additional risks when descaling, especially concerning gas lines and the pilot light. Technicians are well-equipped to handle gas appliances safely, ensuring there are no safety hazards during the descaling process.
  • Professional Assessment: Sometimes, even if you haven’t noticed any significant issues with your tankless water heater, it’s a good practice to have a professional technician periodically assess the unit for scaling. They can identify early signs of scaling and address them proactively to prevent major problems in the future.


Scale buildup in tankless water heaters is a common issue that can compromise their performance and lead to costly repairs. However, by understanding the causes of scale, implementing preventive measures, and maintaining your unit properly, you can keep your tankless heater free from scale and enjoy the benefits of extended lifespan, energy efficiency, and a consistent hot water supply. 

Professional technicians from Einstein Plumbing offer expertise, safety, efficiency, preventative maintenance, warranty protection, and time savings for descaling tankless heaters. By addressing scaling issues promptly and effectively, you can ensure that your tankless water heater continues to provide reliable hot water while avoiding potential damage and repairs.

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