The Rainier Wastewater Department provides for the annual operation and maintenance of the wastewater treatment facility, collection system and lift stations. The purpose of the wastewater operation is to breakdown waste through a biological process and meet federal and state regulations for effluent discharge.

Under order by the Oregon Department of Environmental Quality, the City's wastewater treatment plant is at the end of its useful life and is scheduled for replacement within the next 3-5 years. The project will be the single largest capital construction project for the City and will likely cost between $7 - $10 million dollars. Due to the high construction cost and the small customer base the City will expend great effort soliciting non-local resources to help make the project affordable.

The existing wastewater system facilities include a collection system with standard gravity sewers and two pump stations, as well as an activated sludge treatment plant.

Collection System

The collection system is primarily a standard gravity system with a total of 13.4 miles of piping. The gravity piping is primarily concrete sewer pipe; however, some of the more recent sewer installations have been of polyvinyl chloride (PVC) piping and some of the older installations are vitrified clay pipe (VCP). Though there are areas of new installation, the collection system in general is aging.

Wastewater Treatment Plant

The treatment plant has an average daily capacity of 500,000 gallons per day. The treatment processes include an influent pump station, manual bar screen, conventional activated sludge secondary process, gaseous chlorine disinfection, an outfall to the Columbia River via Nice Creek, aerobic digestion of sludge, two sludge lagoons and land application of the treated sludge.

Rates and Fees

Rates

Sewer rates include two components including a fixed fee and a consumption fee based on metered water usage. The flat fee for all customer classes is $24.45 per month, and the consumption fee is $0.025 per cubic foot of metered water usage. One cubic foot is equal to 7.48 gallons. Residential bills are calculated using a winter averaging calculation. Winter averaging combines the amount of metered water consumed during the prior years winter months and creates a monthly average. The average is then used to set the sewer rate for the next twelve months until the winter average is re-calculated. The theory behind winter averaging is to charge customers for the actual water they discharge into the sewer system and not for water used for warm weather activities, like watering yards, gardens, filling pools, etc. Commercial, Industrial, and rental properties are not eligible for winter averaging.

Connection Fees and System Development Charges

Connection Fee: $100

System Development Charge: $2,645 per equivalent residential dwelling unit.