I keep at least ten cases of Costco bottled water on hand; most of the time there are between 12-14 cases. We go through at least two each month, and I rotate them. Each case is a bit over 4.6 gallons.

Under my workbench there are three five-gallon water bladders, which I dump out and refill twice a year. While I'm prepared to purify this water if need be, it always comes out smelling and tasting like good water when I dump it out.

My water heater holds 50 gallons, but that only works if the water is shut off before contaminants are introduced into the supply.

At a round 120 gallons, the five of us have 24 days of water at 1 gallon/person/day. If we can't trust the water heater, we're at 14 days. I'm always leery of trusting the 1/gallon/person/day figure though, because if it's hot or we're exerting ourselves we could easily drink more than that before any water was used for cooking or washing.

I have carefully prepared a small container of pool chlorine with instructions on how to create a chlorine solution and purify water with it. While writing this post I went into my emergency supplies to estimate how much water I could purify with it, and to my dismay I can't lay hands on it.

While I would have discovered its lack during my Spring emergency gear checkup in a week or so, I'm not happy to learn that I've misplaced it.