Customer Service Office
8:00 a.m. - 5:00 p.m.
Mon. - Fri.)
"High Speed" Flushing
Maintains Water Quality
For decades Portsmouth has used a
conventional citywide flushing program to maintain water
quality. Conducted every spring, conventional flushing consists
of opening hydrants in a specified neighborhood to flush out
accumulated rust and sediment. While effective, this type of
flushing does not increase the speed of water flow through the
pipes enough to dislodge stubborn deposits. Using new computer
mapping technology, the Department of Public Utilities is
developing a new unidirectional flushing program. Portsmouth is
in the forefront in applying this new program.
Unidirectional flushing consists of closing appropriate water
system valves to create one way flow in a neighborhood water
pipe loop and then opening hydrants in a set sequential manner.
This increases the speed of the water flow in the pipes to 6
feet per second or higher. These high velocities produce a
scouring action in the pipes, removing even the most stubborn
deposits. This program is a good tool for use in Portsmouth with
its large inventory of older rusty pipes.
Because of better sediment removal, the benefits of
unidirectional flushing last much longer, use up to 40% less
water than conventional flushing and allows a better response to
localized water quality complaints. Additionally, unidirectional
flushing will test almost all of the water systems valves and
hydrants, identifying those in need of repair or replacement.
The unidirectional flushing program has been designed for a
third of Portsmouth's water distribution system. The remainder will be designed by the end
of 1998. The program will be implemented beginning in 1999.
Flushing is the single most powerful tool
to maintain quality in a water distribution system!
|Your Water System at a Glance
The City of Portsmouth water utility serves water through over 350 miles of water pipe ranging in size from 2
to 42 inches, three pumping stations, five water towers, four ground level tanks, 2,500
fire hydrants, 12,000 valves, 31,000 meters and 210,000 billings producing over $20
million in revenue.