Saturday, March 6, 2010

Sustainable water use - how much does fixing the dripping faucet matter?

While there is much focus on energy usage as a key issue in sustainable development, water usage is also a very important issue.

The USGS has an interesting summary of water usage in the United States for 2000.
One huge take-away is summarized in this figure from the report: A breakdown of total (fresh + salt) water usage.
  • 34% of water is used for agriculture
  • 48% of water is used for power generation
  • 11% of water is for domestic use
  • 5% of water is for industrial use
Reworking these numbers to show only fresh water usage:
  • 40% is for agriculture
  • 39% is for power generation
  • 13% is for domestic use
  • 5% is for industrial use
 So if all domestic and industrial buildings were to obtain the highest level of LEED v3.0 credit for water efficiency (WEp1 and WEc3 (40% reduction in total water usage for 4 points)), that would mean:
  • 8% is for domestic use
  • 3% is for industrial use
A total drop of ~7% vs the 79% combined agriculture and power generation usage.

Put another way:
  • If you could improve efficiency of agriculture's and power generation's water usage by 23%, that would equal all the water used by domestic and industrial consumers combined.
  • It would take less than a 10% improvement in agricultural + power generation water usage to be equivalent to making every home and business in the US maximally water efficient per the LEED v3.0 standard.
So in the big picture, leaky faucets probably don't matter in the way that making agriculture and power generation more efficient would matter... but you don't hear much about that in the news...