Why your well water is cloudy or milky, and how to fix it

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Step 1: Fill a clear glass and let it sit for a while

This one check sorts out most cloudy water.

The Wisconsin DNR uses the bottom-up test for bubbles and the settling test for sand and silt.

If it clears from the bottom up, it's air or gas

Wisconsin lists a few sources of bubbles that aren't a health concern: an air-logged pressure tank, a pump pulling air because the water level in the well has dropped, or gas coming out of solution when water is pumped up from deep in a well. It adds one that can be: a failing driven point well, since shallow wells are more open to nitrate and bacteria.

Methane is the one to rule out. The Minnesota Department of Health says methane can make water look bubbly, milky, or frothy, and it may come with a sputtering faucet or a gurgling well. Methane can build up in closed spaces and explode. Minnesota also recommends testing wells with methane for coliform bacteria and nitrate. Our sputtering faucets page walks through it.

If grit settles out, it's sediment

Penn State Extension says cloudiness from silt, sediment, or clay often comes from runoff, nearby earth moving, or drilling. Wisconsin adds well problems: a new well that wasn't fully developed, a bigger pump pulling harder, or a well screen with holes worn larger over time. See sand in well water.

A sediment filter catches particles. Penn State lists a cartridge filter for mild cases and a multi-layer media filter for heavier ones.

If it stays hazy with scale around the house, it's likely hardness

Wisconsin lists hardness as a cause of cloudy water, and says a water softener is the best option. You'll usually see other clues too: soap that won't lather, spots on dishes, and white buildup in the kettle. See our white crust page.

Cloudy water after heavy rain means test for bacteria

A sudden change in how your water looks can mean surface water is getting into the well. Wisconsin says to watch for this after heavy rain or snowmelt, especially with wells that have shallow or thin-walled casing, wells in pits, and limestone bedrock near the surface.

If your water turned cloudy suddenly, don't drink it until a coliform bacteria test comes back clear. Minnesota recommends a coliform test any time the water changes in look, and bottled or boiled water if the test is positive. Don't boil it if you also have nitrate or arsenic, since Minnesota says boiling raises their levels.

The EPA notes that your local health department may test for free. Virginia Cooperative Extension also notes that cloudy water blocks UV light, so a UV system needs clear water to work.

When to call a pro

Call a licensed well driller or pump installer if sand keeps showing up, if the cloudiness came with sputtering or a drop in pressure, or if a bacteria test comes back positive. They can inspect the well cap and casing for gaps that let surface water in.

Questions people ask