Noise, grit or no hot water? Start here
Is it sediment? Four quick observations
Listen when it heats
Rumbling, popping or crackling from the tank while it is heating, quiet the rest of the time, is the classic sign.
Check the aerators
Sand or white and tan grains caught in faucet aerators or the shower head point to material moving through the hot side.
Notice the supply
If the hot water runs out sooner than it used to, sediment may be taking up space in the tank.
Look, do not open
Leave the drain valve closed. Opening it on a sediment-heavy tank can clog it partly open.
If you smell gas, leave the building, then call the gas utility and emergency services from outside.
If a carbon monoxide alarm sounds, leave the home and call emergency services once you are out.
What the sediment actually is
Two different things end up on the bottom of a tank. The first is material that arrives as solids: fine sand, silt and grit drawn up from the well. The second is material that arrives dissolved and drops out when the water is heated, forming scale that flakes off the tank walls and heating surfaces and collects below. Most well-water tanks have some of both.
Neither is unusual, and neither says anything on its own about whether water is fit for any other purpose. What matters here is what the layer does to the water heater.
What sediment does inside a tank
It makes noise
Water gets trapped under and within the layer. When the burner or lower element heats it, that water flashes into steam and the bubbles collapse, which is the popping and rumbling you hear. The sound is a symptom, not damage in itself, but it tells you the layer is substantial.
It gets between the heat and the water
On gas, propane and oil-fired tanks, heat comes up through the tank bottom. A thick layer insulates the water from the flame, so the burner runs longer to deliver the same hot water and the steel at the bottom runs hotter than it should. On electric tanks, the lower element can be partly buried, which makes it run hot and fail early.
It takes up room
Every inch of sediment is space that should hold water. Combined with slower heating, the result is less hot water and slower recovery, which is easy to mistake for a heater that has simply become too small.
It clogs things
Grit collects in drain valves, can block the dip tube outlet, and travels to aerators and shower heads. A drain valve full of sediment can refuse to close fully once opened, which is one reason not to try it yourself.
Flushing: what it achieves and what it cannot undo
Flushing means draining water from the bottom of the tank with enough flow to carry loose sediment out, sometimes with the cold supply stirring it up. Done regularly on a tank that has not built up a hard layer, it keeps the problem in check, reduces noise, and helps the heater work as it should.
What flushing cannot do is undo years of build-up. Sediment that has sat for a long time can harden into a crust, and flushing may only remove the loose material above it. It cannot reverse wear already done to an element or to steel that has run hot, and it cannot restore an anode that has been used up.
When flushing is not a good idea
On an older tank that has never been flushed, disturbing the layer can clog the drain valve open, or uncover a weak spot that has been sealed by the sediment itself. A technician weighs the age and condition of the tank before recommending it, and sometimes the honest advice is to leave it alone and plan a replacement.
More on this on our flushing and maintenance page.
Find out whether a flush, a repair or a new tank makes sense.
Sediment and scale in other kinds of heater
Tankless units do not collect a sediment layer in the same way, but mineral scale builds inside their heat exchangers and reduces flow and output. They need descaling at intervals that depend on the water.
Tankless coils in boilers scale up on the inside, which is one of the main reasons an old coil stops keeping up. See tankless coil problems.
Indirect tanks collect sediment like any storage tank, and their internal coils can scale over time.
Why it is so common here
Private wells are widespread across eastern Connecticut, in Tolland and Windham counties, in the hills behind the shoreline and throughout the Litchfield Hills. Many of those homes also have older tanks in cellars where they are out of sight and out of mind, and the first a household hears of sediment is the tank starting to rumble. Cold well water adds to it, because a heater that is already working hard against cold inlet water feels the loss of capacity sooner.
What to leave alone
- The drain valve, especially on an older tank
- The temperature and pressure relief valve
- Any fuel, electrical or venting connection
- Water treatment or well equipment, which is outside this service
How the technician deals with it
They start by judging the tank: its age, the state of the drain valve, whether there are signs of leaking, and how much sediment is likely there. On a tank that is a good candidate, they flush it, often replacing a clogged or plastic drain valve with one that will make future flushing easier, and check the anode while they are at it. On a tank that is not, they explain why and talk through options, including replacement with a heater set up for easier maintenance on a well. Prices are given before any work.
Know the cost of a flush or a replacement before deciding.
What affects the cost
- How long since the tank was last flushed, and how hard the sediment has become
- Whether the drain valve needs replacing to do the job properly
- Whether an anode check or replacement is done at the same visit
- The type of heater, with tankless descaling a different job from a tank flush
- Access around the tank and to a drain
How long it takes
A routine flush on a tank that is maintained regularly is a short part of a visit. A first flush on a tank with years of build-up can take much longer, and may be stopped part way if the technician judges it is doing more harm than good. The heater then needs time to refill and reheat.
Sediment questions
Does a rumbling water heater mean it is failing?
Not by itself. The rumble is steam bubbles forming under a sediment layer, and it is a sign the tank needs attention. It does mean the heater is working harder than it should, and on an older tank it can be one sign among several that replacement is getting closer.
Can flushing fix a noisy water heater?
Often, if the sediment is still loose. If the layer has hardened after years without flushing, a flush may only quieten things a little. A technician can judge whether it is worth trying on your tank.
Why is there sand in my hot water but not the cold?
Material that settles in the tank can be stirred up and carried to the taps, especially when the heater is refilling. If the cold water carries grit too, it is coming from the supply rather than the heater, and that part is a question for a water professional.
What are the white or tan bits in my faucet aerators?
Often scale that has flaked off inside the tank. Sometimes they come from a dip tube that is breaking down. A technician can tell the difference and deal with either.
Should I flush my water heater myself?
We recommend leaving it to a technician, particularly on a tank that has not been flushed before. It involves hot water under pressure, fuel or power connections, and a drain valve that may clog open. A technician can also judge whether flushing is still worthwhile.
Does sediment cause a tank to leak?
Indirectly, it can contribute. Steel under a thick layer on a fuel-fired tank runs hotter, and sediment can hide and hold moisture against weak spots. The main cause of tank leaks remains corrosion once the anode is used up.
Would a different heater avoid the problem?
Every heater on a well deals with the well's water in some way. Tanks collect sediment; tankless units and coils collect scale. What makes a difference is choosing a heater that is easy to maintain and setting it up with a good drain valve and room to work.
Can you install a filter to stop the sediment?
Filters and treatment systems are outside what we arrange. If you are considering one, speak to a qualified water professional. The local installers focus on the water heater and how to keep it working with the water you have.
How often should the tank be flushed?
It depends on how much your well delivers. After a first flush, the technician can suggest an interval based on what came out. Some well homes need it far more often than others.