What water treatment system do you need?

We want to install a water treatment system, one that will eliminate Giardia and other nasty bugs for our drinking water only. (Also, the lake water tends to be silty in spring.) We just need drinking water in the kitchen. Could you recommend anything?
—Brenda Muliner

To treat only the water coming from your kitchen tap, you’ll want a point-of-use system. These clean the water in batches and send it to a single tap. Point-of-entry systems, on the other hand, treat all the water coming into the cottage—probably not necessary, unless you plan to drink from your bathtub faucet or your washing machine. Typically, no single treatment method is enough to turn lake water into clean, clear, pleasant-smelling agua; most cottagers need at least one physical filter to first get rid of turbidity (experts recommend a five-micron sediment filter). Depending on your water, you may also need additional filters, for example, a carbon filter, to remove contaminants such as tannins, algae bloom, iron bacteria, pesticides, or herbicides. But this still won’t remove or destroy the dreaded, gut-wrenching Giardia or Cryptosporidium. To tackle these protozoan cysts, you’d require another filter, such as a reverse osmosis filter, or one with a pore size of one micron or less, or a UV system (the UV light damages the DNA and RNA of the microorganisms, so they can’t replicate).

Whichever filters or system you choose, make sure that they have been certified by a standards association such as the NSF or the Canadian Standards Association.