When you look at the raw numbers it does sound very wasteful. It is usually a one part product water to three to five parts per drain. But we think it helps to express this in actually quantities used. Let’s say that you’re 4 people in the house and everyone drinks their requisite 8 ounce cups per day - so this is about 2 litres per person. Then multiply this times 4 people and this means that you’re going through 8 litres per day. Add say 3 litres for cooking and this means your going through 11 litres per day for cooking and drinking - which is a very high estimate. The average family likely goes through about ⅔ to maybe ¾ this amount. Multiply the 11 litres by 5 (which is the worst case scenario for waste from your system) and this makes about 55 litres to drain - which is about 6 toilet flushes or a 5 minute shower. Put this in the context of an average North American’s consumption of water per day - about 320 litres.