Post by Meter Repair on Jan 23, 2011 21:30:27 GMT -5
these are examples of why backflow prevention is important.
this is a direct cross connection between a potable (drinking water) hose and a Reclaim (treated sewage) hose connection.
people do this kind of connection from time to time, more commonly they connect their potable drinking water service to their irrigation well to boost water pressure when well is not producing much, and to prime the well.
i have found at some locations that people sometimes leave the priming hose connected to their well 24/7.
when you have a cross connection, you risk backflow of water of unknown quality or contamination flowing back into your house and city water supply.
in the example of the picture, if both of these valves were open, this person was feeding reclaim water into their home drinking water. generally in my area reclaim water has more pressure than potable, so reclaim water would dominate the potable system within this residence, so when this person opens their kitchen faucet to fill a glass of water, they would be filling it with treated sewage.
you may ask why does someone have this hose configuration? if i recall it was for choice of water for washing this persons boat, its still bad.
Post by Meter Repair on Jan 23, 2011 21:39:07 GMT -5
heres a direct cross connection, originally this persons irrigation system was installed for potable water irrigation, later reclaim water service became available and instead of removing the potable supply, they just tied in the reclaim downstream of the watts no 7 check valve.
1. the watts no 7 check valve is not a testable backflow prevention device, if it fails you don't know it and have no test cocks to test it on a annual basis.
if that watts no 7 fails, and that PVC plastic shutoff valve fails to shut off completely or someone walks by and says Hmm that valve should be ON and turns it on, not knowing about its configuration, could backfeed treated sewage into that persons house.
Post by Meter Repair on Jan 23, 2011 21:47:00 GMT -5
heres a well with chemical injection (most-likely a rust inhibitor) due to alot of iron in the well water in that area, with the supplemental tie in to a irrigation system also fed with the option of potable drinking water.
in this situation, the customer is trusting a Pressure vacuum breaker, which is a testable backflow prevention device that is currently shut off.
also notice on the top of the well, the garden hose connection, most likely for priming of the pump. what happens if those rust inhibitor chemicals get pumped into the house drinking water pipes when the well pressurizes after resident leaves drinking water hose connected to it? not good.
i personally would not trust this situation and i would COMPLETELY isolate the potable drinking water supply from this well.
after i identified this cross connection i immediately installed a Neptune T10DC backflow prevention water meter on the city water connection to protect the neighborhood and notified the customer to remove the cross connection for their health and safety.