Researchers say that the average European uses about 50 gallons of water a day. Folks in sub-Saharan Africa use between two and five gallons of water per day. Where are we? Americans are consuming about 100 gallons of water a day. One way we can lower our consumption is to think about the water we allow to go down the drain without reusing it. For instance, when a person boils water, steams vegetables, or strains pasta, that water could be collected, cooled and used to water plants, flush toilets and more.