Skip to main content
This section is included in your selections.

Private side sewers are the extension of side sewer laterals located outside of the public rights-of-way or easements granted to the Silver Lake Water and Sewer District.

(1) All sewer service connections to district facilities shall be gravity service.

(2) The sewer pipe in the street right-of-way and district easements shall be six-inch diameter, and shall have a two percent minimum grade. Construction in street rights-of-way shall be performed by a licensed side sewer contractor and requires a right-of-way use permit.

(3) Private side sewer pipe for residential property shall be four inches or larger. Side sewer pipe for duplexes, multifamily, industrial, commercial, etc., shall be six inches or larger. Pipe material shall be ductile iron or PVC ASTM D3034, and shall be installed at two percent minimum grade (one-quarter-inch fall per foot). Construction on private property may be performed by owner, but requires a permit.

(4) Pipe shall be bedded with pea gravel or clean free draining sand.

(5) Side sewer shall be inspected by the district prior to backfilling. Side sewer shall be plugged and tested in the presence of the district inspector by filling with water. Leakage rate shall not exceed 0.31 gal./hr. for four-inch pipe and 0.47 gal./hr. for six-inch pipe, per 100 feet of pipe. Existing homes served by septic systems converting to district sewer service are to demonstrate proper abandonment of septic tank to Snohomish County health department standards and WAC 246-272A-0300. The contractor shall provide a copy of documentation regarding sewage pumping to the district.

(6) On private property, minimum cover shall be 18 inches over top of pipe from a point 30 inches out from house and continuing to the connection with the district sewer system.

(7) Parallel water and sewer lines shall be 10 feet apart horizontally wherever possible and have a vertical separation of 18 inches if a vertical crossing is necessary.

(8) No more than 100 feet is allowed between cleanouts. Cleanouts are required for bends equal to or greater than 90 degrees. Cleanout shall be a plugged tee or plugged wye lateral.

(9) All pipe joints shall be rubber gasket type.

(10) When required, “grease interceptor” to be outside the building and be of a size and type certified by a professional engineer licensed in the state of Washington and reviewed by the district.

(11) Backwater valves are required on all side sewers where potential occurs for flow to back into the private service. These valves shall be installed in a riser pipe, meter box, vault or manhole as necessary to allow access for maintenance.

(12) Dwelling units defined by food preparation, bedroom and bathroom areas contained in a structure are primary connections. Secondary connections require preapproval by the district before sewer service can be offered.

(a) Auxiliary dwelling units constructed on an existing served property within an existing structure may be allowed subject to payment of connection charges.

(b) Auxiliary dwelling units constructed on an existing served property in separate structures require separate side sewer connections to district mainline facilities.

(c) Recreational vehicle dumps are not allowed.

(d) Small utility sink and toilet facilities in outbuildings may be allowed to connect to existing side sewers.

(13) Side sewer installs to existing district mainline facilities in right-of-way are subject to special requirements:

(a) Right-of-way permit required. Owner to pay all costs of obtaining the permit and for any costs associated with full compliance with all permit obligations.

(b) Owner to pay all costs of installation of side sewer.

(c) The owner shall enter into a developer extension agreement (DEA) with the district, and will be required to meet the following conditions:

(i) All district or district incurred inspection fees are to be paid prior to and as a condition of connection.

(ii) Compliance with all district standards, conditions, specifications, and requirements are applicable.

(iii) Compliance with all state, local and federal requirements that apply.

(iv) Preconstruction meeting with owner, owner contractor, and district is to be scheduled with the district prior to initiation of construction.

(v) No connection to district facilities can be made without district or district representative on site. [Res. 735 § 1, 2017.]