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WACs > Title 246 > Chapter 246-274 > Section 246-274-405
246-274-400
246-274-410
Agency filings affecting this section
WAC 246-274-405
Location.
Tier 1, Tier 2, and Tier 3 greywater irrigation systems shall be designed and installed to meet the minimum horizontal setback requirements specified in Table I.
Table I
Minimum Horizontal Setbacks
 From edge of subsurface irrigation components From tank and other system components
Building foundations    Â
 Down-gradient1: 10 ft.  N/A Â
 Up-gradient: 2 ft.  N/A Â
Property or easement line 2 ft. Â 2 ft. Â
Pressurized water supply line/public water main 10 ft. Â 10 ft. Â
Interceptor/
curtain drains/drainage ditches
   Â
 Down-gradient: 30 ft.  N/A Â
 Up-gradient: 10 ft.  N/A Â
In-ground swimming pool 10 ft. Â 5 ft. Â
Spring or surface water measured from the ordinary high-water mark2
100 ft. Â 50 ft. Â
Well or suction line 100 ft. Â 50 ft. Â
Public drinking water well 100 ft. Â 100 ft. Â
Public drinking water spring measured from the ordinary high-water mark 200 ft. Â 200 ft. Â
Decommissioned well (decommissioned in accordance with chapter 173-160 WAC) 10 ft. Â N/A Â
Down-gradient cuts or banks with at least 5 ft. of original, undisturbed soil above a restrictive layer due to a structural or textural change 25 ft. Â N/A Â
Down-gradient cuts or banks with less than 5 ft. of original, undisturbed soil above a restrictive layer due to a structural or textural change 50 ft. Â N/A Â
On-site sewage system primary and reserve areas 10 ft. Â N/A Â
1
The item is down-gradient when liquid will flow toward it upon encountering a water table or a restrictive layer. The item is up-gradient when liquid will flow away from it upon encountering a water table or restrictive layer.
2
If surface water is used as a public drinking water supply, the greywater system must be located outside of the required source water protection area.
[Statutory Authority: RCW 90.46.015. WSR 11-02-011, § 246-274-405, filed 12/28/10, effective 7/31/11.]
