The following is intended as informational only. I will not attempt to sell you anything except safety. In fact, I will suggest that you do NOT purchase certain products that may be hazardous to your water system. The courts have deemed that water is a product and not a service to the public. In the U.S. products which are sold for a profit have an implied warranty that the products are usable.
Water has a warranty that it is fit for human consumption.
Most customers manage to contaminate the water they use and normally this contaminated fluid passes to the waste collection system. Unfortunately the water sometimes reverses direction back through the water meter. The most common type of backflow is backsiphonage. Backsiphonage is caused by a sudden loss of pressure in the public water mains. This loss of pressure can be caused by a broken water main, a fire nearby where the Fire Department is using large quantities of water, or simply by opening a fire hydrant to test it.