Portland has fire hydrants every 1,000 feet as the crow flies. That's the standard spacing of fire hydrants in residential areas. In higher-density areas, the standard is every 500 feet. Downtown there are two hydrants for each intersection. Those numbers add up -- to 14,200 hydrants! Hydrants are color-coded to give important information to Portland's firefighters.
Flow & Pressure
Property owners are responsible for the condition of all plumbing and pipes that water flows through after it leaves the water meter at the street. Some water flow problems are temporary. The Portland Water Bureau provides water to all services with a minimum pressure at the water meter of 20 pounds per square inch (psi). Most homes receive water at a pressure of 40-80 psi. We monitor pressure throughout Portland.
Pumps & Pump Stations
Most customers are served by gravity flow. Gravity flow reduces dependence on pumping and its expensive energy needs. It is a reliable method of piping water to facilities and customers. At higher elevations pumps deliver water to customers that cannot be served by gravity feed.
Emergency pump connections at pump stations can be used during a prolonged power outage. A mobile generator or portable pumping unit (gasoline or diesel engine powered) can be hooked up to these connections to supply the distribution reservoir.
Storage tanks are a necessity for a variety of reasons. Water storage tanks have two primary functions: Water tanks guarantee that a particular neighborhood in a service area will have adequate water pressures during all times of day, no matter what the season. Elevating water in tanks improves pressure throughout the system.Water tanks ensure that there is adequate water supply throughout the city to fight fires. Tanks come in all shapes, sizes and configurations.
Tanks may be:
- Buried underground
- Partially buried
- Ground level
- Standpipes (taller than they are round – so they look like a tall cylinder)
- Elevated (either on multiple columns, or a single 'Hydropillar')
Portland has sixty-four tanks. They are constructed either of concrete or steel. The concrete tanks hold from sixty thousand gallons to four million gallons of water. (The transmission tanks at Powell Butte are bigger.) The balance of the other tanks are steel with either riveted, or welded construction that hold from thirty thousand gallons to over five million gallons of water.
Water tank facts:
- The oldest tanks date from 1907 and 1909. Portland's newest tank dates from 2001.
- Some tank sites now have a second use. They are improved as HydroParks – serving both the community as part of the water system and offering tranquil greenspace to nearby residents.
- Water flows through the tanks continuously. Portland Water Bureau control center operators monitor the flows and levels in the tanks to ensure that the water reaching customers’ faucets is clean, cold, and fresh. Water does not “sit” or stagnate in the tanks.
- The water in some tanks in the water system is pumped up to the tank. During power outages the bureau is prepared to deploy back-up generators to ensure reliable supply or has installed generators that start automatically.
- While the tanks are scattered throughout the City for in-town storage, to regulate distribution pressure and to add capacity for fire suppression, they generally do not supply water to the immediate homes and businesses surrounding them. Those homes may be served by a tank that is nearby but at a higher elevation.
- As the Portland Water Bureau develops more sophisticated computer models of future water system demands, storage capacity, and fire flows, capital improvement plans look to address water system needs for additional storage and seismic upgrades for the future.
More than 2,000 miles of pipe deliver water throughout the Portland metropolitan area. That's a lot of pipe that water rate payers maintain. Some mains are 100-years-old -- that's "aging infrastructure" in the bureau's budget discussions.
It's many miles of pipe. If the Portland Water Bureau stretched pipes end to end, you'd have to drive to St. Louis to catch Bull Run out of the faucet.
Pipeline materials consist primarily of cast iron, ductile iron, and copper service piping. New pipelines are constructed of cement-mortar-lined ductile iron. Thousands of valves on the mains allow control during repairs or maintenance.
Property owners are responsible for the condition of all plumbing and pipes that water flows through after it leaves the water meter at the street.