Water Environment Services

General construction notes are required to be included on the construction plans and can be found on the WES (“District”) website or provided upon request. These notes are required, however the Project Engineer may include other applicable notes as they deem necessary.

All work and materials shall conform to WES Rules, Sanitary and Stormwater Standards.

The contractor is required to attend a pre-construction conference with District staff prior to beginning work on the public sanitary and/or stormwater system improvements. At the completion of construction the owner or contractor is required to provide the District a two year warranty bond or security agreement for the construction of the new public sanitary and stormwater systems.

The engineer is required to have an inspector on site at all times during construction of the public sanitary system. 

Existing utility locations are approximate only. In order to protect existing underground utilities, contractors performing work shown on these plans must notify utilities and public agencies at least 48 business hours in advance of, and no more than 10 business days before, beginning excavation, in accordance with the provisions of OAR 952-001-0090. Pothole all crossings as necessary to prevent grade and alignment conflicts. Report all conflicts to the engineer immediately. Protect existing utilities at all times during construction. Call the One Call Utility Notification Center at 503-246-6699 for utility locates

The sanitary and storm systems shall be cleaned and flushed. The catch basins shall be vactor cleaned and the sediment, rock and other debris shall be collected and disposed of in a proper manner. In no case shall debris be flushed down a storm or sanitary sewer for disposal. Debris collected shall be disposed in a commercial landfill or other approved location.

Installation

Public sanitary and storm systems shall be installed in accordance with the manufactures’ recommendations. PVC pipe shall be connected to concrete manholes by means of an approved coupling with an elastomeric gasket, an approved waterstop or flexible sleeve in accordance with the approved plans. Use of Portland cement grout for connection of PVC pipes to manholes will not be permitted.

After the contractor has backfilled the pipe zone of the trench as required, they shall then backfill the balance of the trench, with the type of backfill specified, in one foot (1’) layers, mechanically compacting each layer to 95% of maximum density in roadways and 85% to 90% in all other areas. Maximum relative density shall be determined per AASHTO T-180 In place, density shall be determined per AASHTO T-191, T-205 or T-238. Any subsequent settlement of the trench or ditch during the guarantee period shall be considered to be the result of improper compaction and shall be promptly corrected by the contractor at no expense to the District or the owner.

Sanitary and storm pipes and appurtenances shall be video inspected and tested for leakage in accordance with District standards. Sanitary testing shall include a low pressure air test of the sanitary mainline and service connections, mandrel test of the mainlines, and vacuum test of the manholes Any portion of the sanitary system which fails to pass these tests shall be excavated, repaired or realigned, and retested. The mandrel / deflection testing shall not be conducted no less than 30-days after the trench backfill and compaction has been completed. The test shall be conducted by pulling an approved solid pointed mandrel 95% of the inside diameter through the pipeline on a manhole to manhole basis.

Service connections shall be laid in a separate trench on a straight line and gradient from the tee to the end of the service connection perpendicular to the mainline. At the property line, the sanitary service connection shall be at least 6 feet below the grade at the property line. No service connection shall be laid on a slope of less than two percent, unless otherwise directed by the engineer or shown on the plans. The engineer will provide the necessary surveying and layout to construct each one of the service connection. Each service connection shall be plugged with a mechanical rubber ring plug and marked with 2 x 4 stake placed at the end of each service connection, and shall extend from the end of the pipe to a point one foot (1’) above the surface of the ground. Sanitary service connection will be marked with a green painted stake and storm with a white painted stake. Service connection within the trench shall be marked with an Underground Detectable Tape (green labeled “CAUTION BURIED SEWER LINE BELOW”) or equal shall be placed along the service connection from the mainline tee to the ground surface and wrapped around the green marking stake.

In easement areas, all manholes shall have tamper-proof lids per District specifications, or approved equal. Caution: not all tamperproof lids meet District specifications. The frame and cover shall be extended six inches (6”) above finish grade.

The contractor shall at all times provide and maintain ample means and devices to remove and dispose of all ground and surface water entering the trench excavation during the process of constructing the sanitary system. It is a violation of the District Rules to discharge groundwater, surface water or debris into the public sanitary system. All violations of discharge into the public sanitary and stormwater systems will be enforced by the District. Water and debris shall be disposed of in an approved manner.

Revised 02/11/2026