Distribution storage reservoirs receive water from the terminal storage reservoirs by gravity flow or pumping. Water from distribution reservoirs is delivered directly to customers. These reservoirs are located at the various elevations required to serve customers and have a storage capacity of approximately 220 million gallons. System pressures typically range from 40 to 80 pounds per square inch. Distribution storage reservoirs range in size from 1,000 gallons to 10 million gallons. They are constructed of concrete or steel. They include ground-level reservoirs, standpipes, and elevated tanks.
Consulting engineers have evaluated the bureau's facilities to determine their ability to withstand earthquakes. The Portland Water Bureau has made repairs, and where necessary, lowered water levels in tanks to withstand seismic events.
Mt. Tabor and Washington Park Reservoirs
The Portland Water Bureau maintains reservoirs in Mt. Tabor and Washington Parks.
- Water flows from the Mt. Tabor reservoirs by gravity. This saves on electricity and plumbing costs.
- The water is cold: 1-10 degrees C (35-50 degrees F).
- Security surveillance cameras monitor the reservoirs 24 hours per day.
- The Water Bureau owns all reservoir sites.
- Open reservoirs must be cleaned every six months.