[Descant]

I agree with the above. Run the water awhile if you are concerned about the taste of non-toxic anti-freeze. I'm told drinking it won't hurt you. Mostly, we drain pipes as opposed to pumping antifreeze through the system, so the total amount of anti-freeze is very small going into the septic system. We've never had a problem with anti-freeze going into the septic.
Our septic system was built in the early 80's, and gets pumped every 10 years or so. Mostly weekend use, and overbuilt for the occupancy level so we don't pump as often as we would on the mainland/year round house. When we do pump, we get a few neighbors to do the same so we can split the cost of barging the pump truck out to the island.