science environment

Washington Cracks Down On Mega-Dairy Water Pollution

By Courtney Flatt (OPB)
Jan. 19, 2017 12:45 a.m.
Cows at a dairy farm in Whatcom County, Washington.

Cows at a dairy farm in Whatcom County, Washington.

Eilís O'Neill, KUOW / EarthFix

Washington is requiring dairies with 200 or more cows to apply for  updated water quality permits. The new regulations are meant to curb water pollution from livestock manure.


This type of runoff can cause excessive nitrates in drinking water, which is harmful to infants, adults with compromised immune systems, and women who are trying to become pregnant. Pollution from manure can also contaminate shellfish beds and beaches.

The updated rules could increase the number of dairies that need water quality permits. Previously only a handful of dairies were required to follow stricter standards to manage runoff pollution. Now, about 200 farms will have to meet new water quality guidelines.

One of the bigger changes will be when dairies are allowed to spread manure on crops — dairies often use manure as fertilizer, but too much can cause nitrates to seep into groundwater. With the new rules operators can't spread an excessive amount of fertilizer on the land, and it can't be applied on saturated or snow-covered soil.

If soils test high for nitrate pollution, farmers will have to limit the amount of fertilizer they're spreading on crops or monitor the groundwater.

Dairies will also have to assess the pollution risk caused by their lagoons, which are pools that are part of how dairies manage waste.

"Most lagoons have clay liners that seep into the earth and the ground water," said Sandy Howard, a Department of Ecology spokeswoman. "We're not requiring all of the facilities to dig out the clay liners and put in synthetic liners [right now]. But we're requiring dairies to assess their lagoons and provide information about when they were built, their capacity, and to determine what pollution risk they pose."

Once the assessment is done, the department may make operators line their lagoons, if the pollution risk is too high.

Dan Wood is the executive director of the Washington State Dairy Federation. He said the federation is still reviewing the new rules and wants to make sure they are scientifically sound and affordable, especially in regards to lagoons.

"We can't make an assumption that [lagoons] leak just because they exist. That's not a defensible position based on observations," Wood said. "Dairy farmers are good stewards of the land and intend to be. We have to make sure we're changing things for a reason and not because people have a new idea."

Most affected dairies are in Whatcom and Yakima counties, where there is already an elevated level of nitrates in the groundwater. The permit will not apply to small dairy operations with fewer than 200 cows.

The Washington Department of Agriculture will continue to inspect dairies and will help implement the new rules, which will go into effect March 3.