Slugs in Catchment

[MarkP]

I'm with Jay. Most of the world including most of the US gets water from surface sources that are less clean than a roof. I also think that much can be done to make catchment systems fairly clean in the first place but from the condition of many catchment systems I have seen people generally don't put in the effort and attention to detail to get the most out of said efforts. Frankly the majority of covers that I have seen on catchments do nothing except provide a place for birds to stand while bathing. I am referring to a piece of shade cloth draped over the top of a tank and tied with clothesline. Usually there are pipes that run up over the lip of the tank that guarantee that even a tightly tied cover wont seal out things that can crawl. There are lots of such details that need to be done right but that are usually given a token effort only.

Put in all the bells and whistles required and make sure the installation and maintenance is done right and I would drink it.