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 Down-gradient 1 : 10 ft. N/A Up-gradient: 2 ft. N/A Property or easement line 2 ft. 2 ft. Pressurized water supply line/public water main 10 ft. 10 ft. Interceptor/ curtain drains/drainage ditches Down-gradient: 30 ft. N/A Up-gradient: 10 ft. N/A In-ground swimming pool 10 ft. 5 ft. Spring or surface water measured from the ordinary high-water mark 2 100 ft. 50 ft. Well or suction line 100 ft. 50 ft. Public drinking water well 100 ft. 100 ft. Public drinking water spring measured from the ordinary high-water mark 200 ft. 200 ft. Decommissioned well (decommissioned in accordance with chapter 173-160 WAC) 10 ft. N/A 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. N/A 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. N/A On-site sewage system primary and reserve areas 10 ft. N/A From edge of subsurface irrigation components From tank and other system components Building foundations Down-gradient 1 : 10 ft. N/A Up-gradient: 2 ft. N/A Property or easement line 2 ft. 2 ft. Pressurized water supply line/public water main 10 ft. 10 ft. Interceptor/ curtain drains/drainage ditches Down-gradient: 30 ft. N/A Up-gradient: 10 ft. N/A In-ground swimming pool 10 ft. 5 ft. Spring or surface water measured from the ordinary high-water mark 2 100 ft. 50 ft. Well or suction line 100 ft. 50 ft. Public drinking water well 100 ft. 100 ft. Public drinking water spring measured from the ordinary high-water mark 200 ft. 200 ft. Decommissioned well (decommissioned in accordance with chapter 173-160 WAC) 10 ft. N/A 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. N/A 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. N/A On-site sewage system primary and reserve areas 10 ft. N/A 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.