Why there's sand or grit in your well water, and how to fix it
Sand in well water usually means something changed at the well: a new well that wasn't fully cleaned out, a bigger pump pulling harder, a worn well screen, or a water level dropping near the pump. Sand isn't a health risk, but it wears out pumps and appliances. A sediment filter helps, and a driller fixes the cause.
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Step 1: Let a glass or the tub sit and see what settles
The Wisconsin DNR suggests filling a glass or the bathtub and letting the water sit. If grit drops to the bottom, it's sand or silt. If specks smear into a black powder when you rub them, it's more likely manganese, sometimes with iron. See black specks.
Step 2: Ask what changed
Wisconsin's checklist, plus one clue from Penn State, points to the cause:
| What's going on | Likely cause |
|---|---|
| The well is new | The driller didn't fully develop (clean out) the well, or the screen is the wrong size for the fine sand around it |
| You recently put in a bigger pump or a fixture that uses lots of water | Water rushing in faster is pulling sand with it |
| You're pumping more than before from a sandstone well | Faster flow is scouring the open drill hole and the sandstone is crumbling |
| The well is older, sand has crept up slowly, and flow has dropped | The screen is crusted over, water rushes through what's left, and it has worn larger holes |
| It's late summer or a drought | The water level may be near the pump intake (Penn State) |
Penn State Extension says a water level that drops too low can pull air or sediment into the system. For wells that fill a storage tank, it recommends a low-water cutoff switch that stops the pump before that happens. In Pennsylvania, groundwater is usually lowest in late September or October.
Is sand in well water harmful?
Sand and silt aren't a health concern, Wisconsin says. They are hard on equipment. Sand can shorten the life of appliances that use water and damage your well pump.
Step 3: Put in a sediment filter to protect the house
A sediment filter traps sand, silt, and clay before they reach fixtures. Virginia Cooperative Extension says these are rated by the smallest particle they catch, in microns, and you change the cartridge on a schedule. Penn State lists a cartridge filter for lighter problems and a multi-layer media filter for heavier ones.
A filter protects your plumbing. It doesn't stop sand from entering the well or wearing the pump.
Fix the well itself
| Cause | Fix |
|---|---|
| New well | Let the water run for a couple of days. If sand doesn't clear, ask the driller to come back and develop the well. Wisconsin requires drillers to develop a well properly after drilling. |
| Crumbling sandstone | A licensed driller installs a liner to seal off the sandstone. |
| Worn or crusted screen | A driller replaces the screen, or adds one if there's none. |
| Water level near the pump | Penn State says lowering the pump may help short term, and deepening the well or drilling a new one is the longer fix. It warns a deeper well may not yield more water. |
When to call a pro
Call a licensed well driller if sand keeps coming after a new well runs for a few days, if sand is increasing, or if water flow is dropping at the same time. Call a pump installer if sand showed up after a pump change.
Questions people ask
Is sand in well water dangerous to drink?
Wisconsin says sand and silt aren't a health concern. They're a problem for your pump and appliances.
Why is there suddenly sand in my well water?
Something changed: a new or bigger pump, heavier water use, a dropping water level in a drought, or a screen that finally wore through. Start with what changed recently.
Can a sediment filter fix sand in my well?
It keeps sand out of your faucets and appliances. It doesn't fix the cause at the well, and sand can still wear the pump.
Where this comes from
- Wisconsin DNR, My Water Appears Sandy or Gritty
- Wisconsin DNR, My Water Has Black Particles
- Penn State Extension, Water Facts 3, Using Low-Yielding Wells
- Penn State Extension, Water Facts 7, Managing Your Well During a Drought
- Penn State Extension, Common Drinking Water Problems and Solutions
- Virginia Cooperative Extension, Household Water Treatment