BACKFLOW PREVENTION DEVICES
Federal guidelines under the EPA require that all water supply utilities
implement provisions of the Safe Water Drinking Act to insure that the
water you drink is safe and fit for human consumption.
One of these mandates implements water supply protection through the
installation of a backflow prevention device and requires that the owner
of the backflow device have it tested and inspected each year.
What is backflow?
Backflow is the undesirable reversal of flow of water from its intended
direction in any pipeline or plumbing system. Backflow is dangerous
because it can allow drinking water in plumbing systems to become
contaminated and unusable, possibly even deadly.
What is a cross-connection?
A cross-connection is a physical connection between a potable (drinking)
water supply and a source of contamination. This can be any pipe, valve,
fixture, etc., in a drinking water system that may allow the drinking
water within the system to become contaminated or questionable in
quality. This connection can be created when plumbing is installed, when
using certain appliances, or even simply by attaching a hose to a
faucet. Cross-connections are not always easy to detect, but pose a
serious threat to water quality. Unprotected cross-connections are
prohibited by state regulations, plumbing codes and local codes.
What is a backflow preventer?
Backflow preventers are mechanical plumbing devices installed in a
plumbing system to prevent water from flowing backward in the system. A
properly installed, tested and maintained backflow preventer at the
service entrance to a building or property can reliable prevent the
backflow of water of an unknown quality from flowing back into the
community water system.
How can the water backflow into the system?
Water pressure in a building or home plumbing system can drop suddenly
for any number of reasons, potentially causing a cross-connection. Heavy
water use on a supply line from such incidents as firefighting, a water
main break, or simply excessive demand, can cause sever pressure loss,
resulting in contaminated water being back siphoned into the potable
water system in your home.
Cross-connections
Cross connection can be found anywhere the public water supply connects
with residential or commercial plumbing systems. Here are common
examples of what can happen when cross-connections are found in homes:
- Water from a toilet tank can be drawn back into the
house water supply if the flush valve does not have an
anti-siphon device.
- A garden hose submerged in the water , while
filling a swimming pool or hot tub, can allow water to
be sucked back into the house water supply, if a supply
line pressure loss were to occur.
- When an insecticide or herbicide dispenser is
attached to a garden hose, a pressure drop in the supply
line can cause chemical-laden water can be pulled up the
hose and into the house water supply.
- A sprinkler system that lacks a proper backflow
prevention device can allow dirty water from the lawn to
be siphoned back into the sprinkler head, and flow back
into the house water supply.
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