At the new house we’re trying to go green, more for money-savings than protecting the environment.  One of the ways we do that is to drink rainwater.

We’re “harvesting” water off the roof (some people say “scavenging”, which is probably closer to what it is) and storing it in a couple of five thousand gallon cisterns.  That’s where the water gets the first filtration, taking out big impurities (on the level of leaves).  After the water comes into the house, it passes through a centrifuge (which is a cyclone device, not a spinning device), at about 100 micron filtration.  That’s the size of a thick human hair.

The next filter is a big 5-micron filter, which catches all the really small stuff.  Except for bacteria, which can go down as low as 0.1 micron.  That’s where the last step of the filtration comes in.  We have an ultraviolet light that kills all the bugs that make it through the 5-micron filter.

Except that for months, the UV sensor has been complaining that it’s not getting enough UV rays.  Wednesday night, we cleaned off the sensor, and have been getting readings mostly in the range of 80% to 100% light penetration.  We’re only supposed to worry when the penetration gets below 50 or 60.  So all it took was a clean rag and we stopped the worry we had for our water.  We weren’t too worried – it had passed a health inspection before we moved in, and we continued to shower and brush our teeth using water from the roof.

Next up, though, is a reverse osmosis unit.  Then we won’t be running to the store to get drinking water every week or so.

And that’s a good thing.