Washington County, MN Water Use Rules: Recycled Water Rules (2026)
Key Facts
- Governing section
- Development Code Ch. 4 § 19.5, Graywater Systems
- System classification
- Type III soil treatment and dispersal system
- Design flow
- 60 percent of standard Section 12 flow values
- Toilet waste
- Prohibited from discharge to a graywater system
- Enforcing agency
- Dept. of Public Health and Environment
- Penalty
- Misdemeanor; each day is a separate offense
- Applies to
- Unincorporated townships, not self-regulating cities
Summary
Washington County treats graywater reuse as a Type III onsite sewage system under Development Code Chapter Four, Section 19.5. Adopted as County Ordinance No. 206 and enforced by the Department of Public Health and Environment, the rule applies across unincorporated townships, cuts the design flow to 60 percent of standard values, and bars toilet waste.
19.5 Graywater Systems
(1) General. Graywater Systems shall be classified as a Type III system and must meet or exceed the following requirements:
(A) Employ 60 percent of the flow values in Section 12.
(B) Meet or exceed applicable requirements of Section 13, Section 14, and Section 15, except as modified in this part.
(C) Meet or exceed the requirements of Section 17.
(D) Meet or exceed the requirements of Section 16.2 and Section 16.3.
(2) Toilet Waste. Toilet waste must not be discharged to a graywater system.
(3) Sewage Tanks. The liquid capacity of a graywater septic tank serving a dwelling must be based on the number of bedrooms existing and anticipated in the dwelling served and shall be at least as large as the capacities given in Table VIII.
Full Breakdown
3. Toilet waste is flatly barred from entering a graywater system; blackwater has to go to a separate treatment train. The septic tank feeding the system is sized by bedroom count under Table VIII: a two- or three-bedroom home needs at least a 1,000-gallon first tank plus a 500-gallon second tank, four-to-five bedrooms need 1,000 and 1,000 gallons, six-to-seven need 1,250 and 1,000, eight-to-nine need 1,500 and 1,000, and homes with ten or more bedrooms scale up under the formula 2,000 gallons plus 150 gallons for every bedroom past nine.
The chapter was adopted as Washington County Ordinance No. 56 and Chapter 145A, and it governs all areas of the county other than cities and towns with their own compliant SSTS ordinance, so incorporated cities such as Woodbury or Stillwater that run an approved program of their own are outside its reach.
Violations & Fines
Operating a graywater system that skips Section 19.5's flow, treatment or tank-capacity requirements, or that routes toilet waste into it, violates Chapter Four. Section 26.1 makes any violation of the chapter a misdemeanor, with each day a violation continues counted as a separate offense; the Department of Public Health and Environment issues citations under the county's Administrative Ordinance and may pursue civil injunctive relief under Section 26.3 to force corrective action.
Frequently Asked Questions
Can I send toilet waste to a graywater system in Washington County?
Does this graywater rule apply inside Woodbury or Stillwater?
How big does my graywater septic tank need to be?
Sources & Official References
Other rules in Washington County
Compare Washington County to another location·View the Minnesota water use rules overview
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