That's good to know. I have been digging in areas that are heavy clay and bringing that toward the sides of the house and packing it down with one of those heavy square tamping things. I think I have the problem licked, I just had heard that water sometimes takes a while to show up in the basement. Still, I'm waiting for some good steady rain so I can can go out in the yard and watch how things flow and then, later, see if the basement remains dry.

Is this the correct way?? I have 3 lines that backwash (including the RO unit). Do I need three sets of traps or can all 3 tie into the same one?

Thanks for everyone's great input. To answer a couple of questions, the hot water loop is separate from the cold water lines. It is insulated the entire way from one end of the house to the other. There is an electric pump next to the water heater that moves the hot water through the pipes, delivering hot water quickly to most any faucet. The hot water in the cold water pipe is due to the hot attic. The weather has cooled significantly here in SoCal and I can tell the difference. Today was about 70 degrees, and the "cold" water comes out room temp instead of hot when we have the 100 degree days. I know the problem. I was just wondering if there was an easy solution. Inslutating the cold pipe? Or the other one that makes sense - removing the insulation below the pipes, and tenting it over the pipes so maybe the air conditioned rooms below will keep the space with the pipes a bit cooler than when they are fully exposed. Or, just live with it. Maybe an under-sink chiller hooked up to the small filtered water faucet is in order.

I think what Green-Designs is pointing out is what I also have: that the coliform isn't coming from deep in the rock formation where your well is drawing its water. It's coming from some point in the casing, piping, supply lines etc. that brings the water up to the surface and then on into your house and out through the tap. Unless your well is like mine here on the farm (a hole lined with laid up stones) it was drilled into rock, then above the rock the hole was line with metal pipes in the soil running up to the surface (the casing). Depending on your system design either a pump is lowered down into the well through the casing and pipes come up from the pump with the water or pipes with a foot valve are lowered down through the casing into the standing water with a suction pump attached above that to raise the water.. At the well head the water is redirected below the frost level typical for your area in pipes through the ground into your house. From thence to a pressure tank and then out to your taps, etc. Somwhere in that system surface water carrying coliform bacteria from some critters' gut (large or small, human or non-human) entered the system contaminating it. It could have been a one-time event, but most likely the breach is still there, and even if more bacteria is not now coming, it could in the future. And any thing that increases soil water (on surface or just in the soil) carries the possibility that it will happen again. The other possibility here is that the breach is inside your house, and so unaffacted by high soil moisture. For instance perhaps you have a sewer drain and supply line too close together and a small leak has formed in both allowing an exchange of contents. Not likely, but it could happen. Or perhaps you have had a back flow of coliform carrying water through a tap connection - washing machine feed hose, an icemaker supply line or an outdoor hose bib is where this might have happened. Maybe a plumbing repair introduced it originally. That's why it's possible that a single, or even a series of shocks might eliminate it. But also why, if it continues to test positive, you may need to do more work to find and fix the problem. I wouldn't hesitate to shock it and then retest, upstream of your UV system, of course. The bad test is "on the record" now anyway, so you've nothing to lose. It's inconvenient to shock, and a little stinky as you will have to run the chlorinated water out. But maybe it will do the trick. Your county (or state) health department has dealt with this countless times before and can give you good advice on how to do it. They won't think you are Typhoid Mary out to infect the whole region. It's just a common well problem that needs to be addressed. Scads of people with private supply systems have been through this. Unless your water supply is located in an area with tons of animal manure run-off, chances are it will be no big deal to address. That's where your buyers went off the deep end. If you want to live in an area with private water and/or septic systems you have to expect this sort of thing from time to time. (The drowned squirrel that decayed in my well, was unusual, though. Definitely a worst case example!>) HTH L.