If you've been having trouble with your water heater, chances are you've been searching the issue only to find yourself here. Sediment buildup is a common problem that can cause slow heating, fluctuating temperatures, or no hot water at all. Removing it is a fairly simple fix, and we'll walk you through it.
What Is Sediment Buildup?
Sediment buildup happens in all storage-tank water heaters. During heating, minerals like calcium and magnesium form solid sediments that settle to the bottom of the tank. Left alone, a large buildup causes problems that worsen over time.
How Do I Know I Have Sediment Buildup?
Signs include fluctuating water temperatures (too hot to lukewarm), a diminished supply of hot water, rising energy bills, and rumbling or popping sounds when the heater runs.
Is Sediment Buildup Dangerous?
No, sediment itself isn't dangerous, but it hurts your heater's ability to maintain consistent temperature and efficiency. Severe buildup can clog drain valves, block water lines, and even cause tank failure if left untreated.
Can It Be Avoided?
Sediment buildup can't be prevented completely, but you can keep it in check by flushing the tank about twice a year. You can hire a plumber, or follow this guide and save money — and still have the unit serviced annually to prolong its life.
What You'll Need
Gather your supplies before you start: a garden hose, a bucket, towels, channel-lock pliers, and this guide.
Our Top Picks
Magnesium Water Heater Anode Rod
Sediment and corrosion go hand in hand — a fresh anode rod slows the corrosion that worsens buildup.
RIDGID 31010 10-inch Straight Pipe Wrench
You'll want a solid wrench to open the drain valve and remove the anode rod while clearing sediment.
Final Editorial Verdict
Turn Off the Power
Water heaters run on gas or electricity — turn off the power before touching anything to avoid electrocution. It's a good idea to turn the heater off the night before so the water can cool. For electric units, find the breaker assigned to the heater. For gas units, find the thermostat (usually a red knob) near the pipe entering the unit, note the current setting, and turn it to the lowest "pilot" position so incoming water isn't heated.
Turn Off the Water Supply
Locate the cold water supply valve, generally where the cold pipe enters the top of the tank, and turn it off. Water can reach 140°F, so take care to avoid burns.
Prepare to Drain
Water heaters commonly hold 40–50 gallons (some 80+). Decide where the water will go — the garden, totes for reuse, or the driveway. Connect the garden hose to the drain valve at the bottom with channel locks so it doesn't pop off, and open a nearby faucet to prevent a vacuum.
Drain the Water
Open the drain valve, and optionally the pressure relief valve at the top to improve flow. Be careful — an old valve could break. If you're draining hot water, wrap a towel around the valve and keep pets and children away from the scalding water and steam.
Test for Sediment
After about 20 minutes, fill a small bucket and let it settle for 60 seconds. If the water is cloudy or has sediment at the bottom, drain another 10 minutes and test again. Once it's clear, you're done draining.
Finishing Up
Close the drain valve and remove the hose. Open the water lines and let the tank refill — you'll hear air spurting from the open faucet until it's full. Don't turn the heater back on until full pressure returns and air stops. Reset the thermostat to its original setting, close the relief valve, wait about 30 minutes, and test the temperature at the nearest faucet.
Conclusion
Sediment buildup is normal and can't be fully prevented, but biannual maintenance prevents major problems. Always work with extreme caution because of the risk of burns from the hot water a heater produces.