WATER DISTRIBUTION AND

STORAGE

J.D. DouglasSt. Albans District Office Supervisor

August 21, 2018

Distribution Components

Storage Tanks

Pipes

Valves

Hydrants

Service Connections

Meters

1

Storage Tank Purposes

Constant source of treated water

Fire flow

Short-term emergency supply

2

Storage Tank Types

Ground level

Standpipes

Reservoirs

Elevated tanks

3

RESERVOIRSGround Level

STANDPIPESStandpipe

GROUND LEVEL TANKSReservoir

ELEVATED STORAGE TANKSElevated

ELEVATED STORAGE TANKSElevated

ELEVATED STORAGE TANKSConstruction Materials

• Loss of disinfectant (chlorine) residual

• Bacterial regrowth

• Disinfection byproducts

• Sedimentation

Concerns

• Watertight roof

• Screened vent

• Drain not directly connected to sewer or storm drain

• Draining for cleaning should not cause loss of pressure for customers

• Fencing with locked gate

• Locks on access doors

• No Trespassing signs

Inspection Items

Surfaces protected by coating (paint) and/or cathodic protective devices.

Paints certified by ANSI/NSF Standard 61

Cathodic protection: Attaching a block of magnesium by an electrical conductor. Excess electrons are bled off the surface to the magnesium cathode which then corrodes rather than the tank surface.

Protection

• Disinfect – WV requirements are more stringent than AWWA Standard C652.

• WV requires 3 consecutive sets of samples at 24-hour intervals.

New Tank Disinfection

SECURITY FENCETank Fencing

• Pipes, fittings, valves, and fire hydrants shall conform to ANSI/NSF Standard 61.

• Pipes and fittings containing more than 8% lead cannot be used.

Distribution Materials

2-inch diameter or larger

Usually 6-inch diameter

Water Mains

Cast Iron – Once favored, but not often used anymore.

Ductile Iron – Push-on joints have the advantage of being flexible for earth movements.

Asbestos/Cement – Also flexible, but some concern about asbestos fibers (potential carcinogen).

RCP (Reinforced Concrete Pipe) – Steel pipe wrapped with wire, embedded in a concrete sleeve. Used for large mains that need diameters of up to 12 feet.

PVC (Polyvinyl Chloride) – Light with good hydraulic characteristics, but some concern about release of vinyl chloride (potential carcinogen).

Materials Used

• 30 psi static - no flow conditions

• 20 psi - all conditions, including fire flow

Minimum Pressures

• Minimum cover 36”

• Recommend 42”

• Mains less than 8” diameter and within 5 feet of main highway 42” deep

High traffic areas – mains should be buried 42” deep

Cover Depth

• Parallel -10 feet horizontally, edge to edge

• Vertical – Bottom of water main at least 18 inches above the top of the sewer.

• At crossings, place the midpoint of a 20-foot joint of water main over the sewer so the joints will be at least 10 feet from the sewer.

Water/Sewer Line Install

Minimum water main diameter is 6 inches to allow for installation of fire hydrants.

Fire Hydrants

Most important use of fire hydrants is for public protection

Other uses

• Flushing water mains

• Filling tank trucks

• Construction use

Fire Hydrants

Wet barrel – warm weather Not in WV

Dry barrel – cold weather -- Automatically drains water out of hydrant so it won’t freeze. (has gravel pocket)

Draining type frost-proof yard hydrants are not permitted in WV

Hydrant Types

Water Loss

TOO MANY LMEAKS...Water Loss

All repairs and new installations need to be properly disinfected and bacteriological tested per AWWA Standards before placing in or returning to service

If a Boil Water Order is issued Policy DW-23 from the Environmental Health Procedures Manual needs to be followed.

Repairs

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Questions