How do you fix a hot water heater

Follow these steps below or scroll to the bottom to see and download a concise infographic of the process.

A typical water heaters last somewhere between 7 to 14 years. As they get older, mineral deposits from Columbia’s water supply slowly build up inside the tank. This buildup makes the unit work harder, reduces efficiency, and shortens the amount of hot water available. Sometimes a professional flush or repair can restore performance. Other times, replacing the unit is the smarter and more cost-effective option. At Highline Plumbing, we take the time to evaluate your system and explain what makes the most sense for your home or business.

Changes in how your hot water behaves are often the first clue that something isn’t right. If you’re running out of hot water quickly, hearing popping or banging noises, noticing rusty-colored water, or seeing moisture around the tank, your water heater is likely struggling. Even a small leak or a faulty valve can turn into a much larger problem if it’s ignored.

Tankless water heaters are designed to last longer and use energy more efficiently, but they still need regular service. Over time, mineral scale, corrosion, and heavy usage can reduce performance or cause components to fail. Our technicians are experienced with tankless systems and can diagnose issues quickly, whether the unit needs descaling, part replacement, or a system upgrade. Follow these simple steps below to do it yourself:

How to Flush a Tank Water Heater

Flushing a traditional tank-style water heater once a year helps remove sediment that builds up from Columbia’s mineral-rich water. This improves efficiency, extends the life of the heater, and restores hot water performance.

What you’ll need

• Garden hose

• Bucket or floor drain

• Flathead screwdriver

Step-by-step

1. Turn off the power

   • Gas heaters: Set the gas valve to pilot

   • Electric heaters: Turn off the breaker

2. Turn off the cold water supply
   Find the valve at the top of the tank and shut it off.

3. Attach a garden hose
   Connect the hose to the drain valve near the bottom of the tank. Run the other end to a floor drain or outside.

4. Open a hot water faucet
   This prevents vacuum lock and allows the tank to drain properly.

5. Open the drain valve
   Let the tank empty completely. If the water comes out cloudy or gritty, that’s sediment being flushed out.

6. Flush with fresh water
   Turn the cold water back on briefly while the drain valve is still open. This stirs up and removes remaining sediment.

7. Close the drain and refill
   Once the water runs clear, close the drain valve, remove the hose, and turn the cold water back on. Leave a hot faucet open until air is fully purged from the system.

8. Restore power
   Once the tank is full, turn the gas or electric back on.

How to Flush a Tankless Water Heater with White Vinegar

Tankless water heaters need regular descaling to prevent mineral buildup from clogging the heat exchanger. Most manufacturers recommend doing this once per year.

What you’ll need

• 2 to 3 gallons of white vinegar

• Submersible pump

• Two washing-machine hoses

• Bucket

Step-by-step

1. Turn off the heater
   Shut off the power and gas supply.

2. Close the water valves
   Turn off the cold and hot isolation valves on the unit.

3. Connect hoses
   Attach hoses to the service ports on the heater and place the other ends into a bucket.

4. Add vinegar
   Pour white vinegar into the bucket and place the pump inside.

5. Circulate the vinegar
   Turn on the pump and let the vinegar circulate through the heater for 45–60 minutes. This dissolves scale and mineral buildup.

6. Flush with fresh water
   Turn off the pump, drain the vinegar, and open the cold water valve briefly to rinse out the system.

7. Disconnect and restore
   Remove the hoses, close the service ports, reopen the hot and cold valves, and restore power and gas.

Why Flushing Matters

Sediment buildup is one of the top causes of:

• Reduced hot water

• Loud popping noises

• Higher energy bills

• Shortened water heater lifespan

At Highline Plumbing, we flush both tank and tankless water heaters as part of professional maintenance and can spot early signs of wear before they become expensive failures.

If you’d rather not tackle it yourself, our licensed Columbia plumbers can handle it quickly, safely, and correctly.

Highline Plumbing provides complete water heater repair, maintenance, and installation services in Columbia, Missouri. From traditional tank systems to high-efficiency tankless and heat pump units, we help you choose the right solution for your needs — and we stand behind our work with honest advice and dependable service.

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