Minnesota needs a better understanding of greywater

February 10, 2019 GMT

What happens when a septic system violates your religion?

Four families in Fillmore County are at risk of losing their homes and livelihoods due to a government lawsuit against them. Why? These families piped their bathwater out to their cow field.

Does that sound crazy? I thought so when I was called in to be an expert witness in a trial in Preston.

Four Swartzentruber Amish families are in court against the Minnesota Pollution Control Agency and Fillmore County. The government is fining them thousands of dollars and asking for the court to force 24 hours a week of community service work until they install a septic system. They could even face jail time.

This case is now in the 90-day window the judge has to render his decision.

Though perhaps hard to understand for non-Amish, being forced to install a septic system goes against these people’s core religious beliefs, so they are asking to use a safe alternative instead.


These families use outhouses, so the water whose disposal is under dispute is just from their baths, sinks and laundry. This is called “greywater.”

Is their greywater an “imminent threat to public health,” as alleged by the county?

Imagine you just took a bath. You’ve washed off dirt, dead skin and soap. After stepping out, does your bathwater become hazardous? If you piped that water into your own yard would it be a public health threat? So long as it soaks into the ground and is not too close to a waterway, 20 states (and their health regulators) agree the answer is no. A family’s greywater can typically be safely disposed of in their own yard, with no increased risk to health. If you were sick and you’ve left germs in the water, anyone likely to encounter those germs already lives with you, plus, they’d have to dig in your yard to get to the germs.

Larger scale systems, like in a hotel or apartment building, require more safety precautions since the people generating the greywater don’t live together. There are an estimated 22 million people using greywater in the United States, but there has never been a documented case of illness from it.

The system the Amish are asking to use as a safe alternative is common in many states with diverse climates. The risk from these residential systems is so low some states don’t require permits or inspections. Nationwide, 20 states allow residential reuse of greywater and some actively encourage it with financial incentives, free education and rebates for materials.

Greywater systems are encouraged because they save water, reduce energy needed for water treatment, and alleviate overloaded septic systems. Minnesota, in contrast, treats greywater like sewage, requiring it to be discharged into a modified septic system they (confusingly) call a greywater system.


Residential greywater systems can be surprisingly simple. The best management practice is to flow the water into “mulch basins,” trenches filled with wood chips, located near plants. Wood chips filter the greywater before it reaches the soil, where nutrients and germs are removed by soil micro-organisms, just as occurs in a septic system leach field.

Even though the county and Minnesota Pollution Control Agency have no experience with this type of system, they claim it won’t work in Minnesota. One reason they cite is the climate — it freezes. Since this system relies on the same natural soil treatment septic systems use, it will work just as well as they do, albeit with much safer water to start with since toilet water is not included.

I encourage the county to look outside the borders of Minnesota for guidance on how to safely and reasonable regulate greywater. This would help the current religious freedom issue at the root of this trial, as well as pave the way for environmentally minded Minnesotans who might want to reuse greywater in the future.

These cases against the Amish sound extreme, unnecessary and overly punitive. When I learned that the Amish represent less than 1/10th of a percent of the state population, but were subject to 41 percent of MPCA’s lawsuits over the past three years, it also sounded like discrimination.