Back flow valves remind me of my uncle's lawn

Wednesday, April 25, 2007

Here's a little public health reminder, courtesy of the Lewisburg Water and Wastewater Department, along with an old story that arises from a scatological thought born of a my uncle's new lawn.

We'll start with the serious business and finish with the funny business punch-line.

City officials want you to know that it's important to have a back-flow valve on your garden hose spigot. Back-flow is just what it sounds like, water flowing in the opposite direction of its normal flow. It's possible if there's a piping arrangement that can allow liquids other than drinking water to enter the water system. It can happen, according to the city water department, if there's a change in water pressure.

It's not hard to imagine the various reasons. There might be a water line break and pressure in the system forces water to continue to serve other customers. Or, there might be a tremendous draft of water from a fire hydrant by a fire truck.

The city gives two examples on how serious a back-flow can be if we're not careful about our pipes.

A potentially hazardous cross-connection occurs every time someone uses a garden hose sprayer to apply insecticides or herbicides in their yard. Spring is a typical time to worry about the appearance of a lawn, so the city's warning seems well timed. If there's a change in water pressure in the pipes, the direction of flow can change and there's a chance that lawn chemicals could be sucked into the household water supply pipes.

It's not a theoretical situation. A North Dakota town's residents had to be rationed drinking water from the National Guard while the town's water distribution system was flushed and disinfected following contamination by DDT. That was years ago, but the investigation revealed two residents who sprayed DDT had made direct cross-connections to their homes. A back-flow condition occurred and DDT was sucked into home piping systems and out into the town's water distribution system.

You may not be leaving messages on a telephone answering machine like Alec Baldwin apparently did earlier this month (followed by his estranged wife's decision to release the recording to the media), but neither do you want to treat your family like weeds or pesky insects.

The solution is frequently called a back flow valve. Technically, it's called a hose-bib vacuum breaker and it's available at virtually any hardware store and it screws on the garden water faucet.

Less exotic contamination can result if a garden hose is used to clear a stoppage in the sewer line. In this situation, a home's drain pipe is to be unclogged, but the hose is like an open avenue to the sewer.

Those are the cautionary tales that come in the city's public heath warning about unintended consequences. Here's another that spins off the concern about our own solid waste being a threat, although this cautionary tale doesn't have a local application.

My uncle Butch built a house in a fast-growing southern town and he was eager to have a lush green lawn. He didn't fertilize it with chemicals sprayed on with a garden hose. He took advantage of an offer from the town's sewage treatment plant. The town was running low on places to dispose of sludge from the sewage treatment plant. The stuff was highly treated to remove odor, but the nutrients were still there and the stuff was delivered for free and sprayed on lawns all across the town.

So, Uncle Butch signed up for the free fertilizer and irrigation. His lawn grew like crazy. It was so crazy that he soon realized there was something else growing in his lawn. It was tomato plants, and lots of them. So, there was another bumper crop of tomatoes that year. Do you think people were eating all of them?

The inside scoop on this story is that the human digestive system does not breakdown tomato seeds. We just pass them along.

Can you imagine what the neighbors were saying? Maybe it was something like, "Hey, did you hear what happened to Butch?" Or maybe it was, "Oh, no. Thanks. We've got tomatoes."

So, there's a ton of advice from the city and my uncle's tale on unintended consequences.