Is Well Water Safe for Horses?

Step 1: Test the well water every year

An Ask Extension answer, quoting Oregon State University Extension publication EC1558, says to test well water every year for E. coli bacteria and nitrate. The University of Georgia Equine Program says extension offices test water in the barn and the pasture, not only in the home, for pH, minerals, E. coli and more.

A state-certified lab or your county extension office can run the test. Our guide on how to test well water shows how to find a certified lab in your state. One example: the Penn State Agricultural Analytical Services Lab charged $50 for its basic livestock water package, and $75 with total coliform and E. coli, when we checked on November 3, 2026. Those prices are for that lab only. A home bacteria test is a first screen. A certified lab confirms it.

Step 2: Read the result

The Oregon State text says E. coli bacteria should never be in well water. Penn State Extension says fecal coliform in livestock water should be near zero.

Penn State Extension gives these numbers for livestock water too. A pH of 6.8 to 7.5 is the preferred range. Total dissolved solids under 1,000 ppm are considered safe to drink.

Ohio State University Extension says to treat a well after a water test shows bacteria. Our advice: any coliform result means the well needs treatment and a second test. The steps are in how to treat a livestock well and stock tanks.

Step 3: Fence the wellhead

The Oregon State text says to fence horses and other livestock away from wellheads, and to keep livestock and manure piles at least 100 feet from wellheads. Mississippi State University Extension says livestock grazing near the well access can bring bacteria into a well.

Step 4: Keep the troughs clean

The University of Georgia Equine Program says water troughs can breed bacteria, on well water or city water.

NC State Extension says to scrub the sides and bottom of a tank and rinse it well. A tank with no drain is easier to empty if you turn off the water and let the stock drink it dry. NC State says a few minutes of tank care each week helps.

Step 5: Watch for a change in the water

The Penn State lab says odors and tastes can make livestock drink less water. Penn State Extension says to test whenever a problem is suspected. Our advice: treat a new smell, color or taste as a reason to test again.