Is a backflow device required with a water pump?

[Gil Bang 25951]

A friend of mine lives nearby, but it's a very rural area.   She's a single woman and doesn't really have any family.

Her neighborhood suffers from low water pressure, so she has a booster pump.  

At the street, there's a main shutoff, with a backflow device.  About 30 feet away is the booster pump.  The district water feeds the pump, and the pump boosts the pressure.   At the pump, there's another backflow device, right where the water comes out of the pump.  That device is plastic and is leaking.  I cannot find a replacement. 

I'm racking my brain, and cannot figure out why it's necessary.   I get the backflow at the main line, but why at the pump as well?  If I could eliminate the leaky backflow, it would be quick and easy to fix the leak forever.

Edited September 5, 2023 by Gil Bang

[Dewey 3286]

What else is she having problems with?

[Hefeweizen 5320]

Most of the time a backflow preventer is code required due to what is called cross connection hazard.  For example if you have a well connected in addition to your service.  Sometimes it is because you have water anticipated to become low in disinfectant residual, such as with sprinklers.  
 

For a booster pump it seems completely unnecessary, most pumps will have a check valve to prevent reverse flow.  Even if it did, so what?   Without a hazard to protect against I would think she can talk to the service provider and get rid of the BFP.  
 

Edit :  you’re talking about the check valve at the pump.  That one is more needed than the other as it prevents issues with the impeller if it’s not designed to rotate in the reverse direction.  More important when there are solids in the liquid but could still be an issue depending on pump model.

 

 That kind of check valve is cheap.

Edited September 5, 2023 by Hefeweizen