Glass of Water in Sunlight ca. 2000
According to The Water Encyclopedia (1990) for a family of 4, the average family uses 29000 gallons per year for baths, 35000 for toilets, 12000 for laundry, 36000 for lawn, 3000 for cooking and drinking, 1400 for garbage disposers, 5800 for dishwashing, 3500 for washing cars. I think some of these numbers are high, but the survey was done in 1990. One newer survey shows usage at about 118,000 gallons per family of 4 per year. I read an overview of water usage/treatment/etc., in Minneapolis (found at this link, http://www.ci.minneapolis.mn.us/water/ under “Water Facts”), and it states that in Minneapolis, 60-70 gallons per capita a day is being used. I took the high-end number, multiplied it by 365, then multiplied that number by four. I came up with 102,200, which is lower than the national average, but still quite high. How can we start conserving?
Water Quality:
Because of the way we have our water systems set up, we essentially are using top quality, filtered, drinking water for all of the above uses. Even though water is inexpensive (in this country), do we need to use top quality water for all of the normal household uses? 
Conservation:
How can we conserve our water? By reducing consumption. First, that green lawn is consuming about 30% of all the water we use, or 35,000 gallons per year. Just having a “not so green” lawn can save 35,000 gallons. It’s not going to save much in costs, but it sure can save a lot in resources. Or what if we could capture waste water from baths, laundry, and dishwashing, and lightly filter the water and use that for the lawns? That could reduce the consumption by 35,000 gallons, while still allowing for green lawns.
Get a front load washing machine. Top load washing machines use about 70 gallons per load, require more detergent, and are harder on clothes because the agitator twists the clothes. Front loaders use much less water. Our Frigidaire Gallery front load machine uses 35 gallons per load, uses less detergent, and is gentler on clothes (no twisting). Right there, we’re saving 50% of water usage, which in our case is about 5000 gallons. Some Asko washers take 12 gallons per load, an 80% savings. If we were to switch to that, we would save another 3500 gallons above what we are using right now. Or, if you go from a traditional top loader to an Asko, you could save 9000 gallons per year. (This assumes 3 loads per week)
Get a more efficient dish washer. I wrote a review of 2 dishwashers a couple of years ago. The Maytag Jetclean II MDB8600A vs the Miele G841SC. The Maytag uses 10 gallons on the heaviest load, and the Miele uses 6.4 gallons on the heaviest load. That’s a 36% savings.
Turn off the faucet while brushing. 3 gallons go down the drain each minute while brushing. This alone can save 8700 gallons of water.
Run 3 kids through the same bath water. Each bath takes about 30 gallons of water.
If you have an older toilet, it can use 4 to 7 gallons per flush. New toilets use 1.6 gallons per flush. The average person flushes 4 times per day. Changing the toilets can save 14,000 gallons per year.
Fix the leaky toilet. If the toilet refills randomly during the day, it’s leaking. Leaky toilets can consume 200 gallons per day!
Summary:
Our usage looks like this:
Laundry: 4 loads per week at 35 gallons per load = 7280
Dishes: 7 loads per week at 6.4 gallons per load = 2329
Toilet: 4 flushes per day per person at 1.6 gallons per flush = 9062
Showers: 6 showers per week at 20 gallons per shower = 6240
Baths: 4 baths per week (2 kids per bath) at 15 gallons = 3120
Lawn: we don’t water the lawn = 0 (yes it was brown this summer, but it is green now)
Car wash: 2 cars twice per year (spring and fall) at 10 gallons per = 40 gallons
Brushing Teeth: 8 brushes per day at .5 gallon per brush (water off except rinse) = 1460
Cooking and drinking: 3 gallons per day = 1095
TOTAL: 30,626 gallons per year for our family.
That is pretty close to what our water meter reads. Last year, we read usage at the meter at about 36,000 gallons. That means that we use about ¼ the amount of water that the average family uses. We’ve made appliance purchase decisions based on how much water they consume (dishwasher and washing machine) and are very careful to turn off the water while brushing. We’ve also installed low usage toilets, and low flow shower heads. All this has paid off in terms of saving water.
The Future:
The home of the future will be built to conserve even more water. For some people, the thought of re-using water may not seem like a good idea, but there are systems that can be installed in a typical house that appropriately filter the water so that re-use is possible. The water from baths, showers, dishwashers and washers is typically called “grey water” or “gray water”. There are excellent resources out there that detail how grey water can be used around the house, once it is appropriately filtered and stored. The home of the future may incorporate grey water systems to irrigate the lawn, or for washing the car, or for flushing the toilet. These systems exist right now, but cost somewhere in the neighborhood of $15000 and require some retrofit of the plumbing in the house. For those of you that are interested in more about grey water reuse, there are several good websites, including this one in particular: http://www.oasisdesign.net/ .