Why Harvest Rainwater?

There are many reasons and benefits:
  • As Marin Municipal Water District customers, we get our water primarily from behind dams on Lagunitas and Nicasio Creeks. A large amount of historical salmon habitat in Marin County has already be lost behind those dams.
  • Our local water supply can't meet our demands, so an additional twenty-six percent of the water we use is diverted from the Russian and Eel rivers, endangering already devastated salmon runs in these watersheds as well.
  • Enormous volumes of water are lost each winter as rain pours off our roofs and other impermeable surfaces into storm drains. Then during the hot, dry summer months 30-50% of our water use goes to irrigating our landscapes! (See where this is going?) Let's tap into a winter resource (storm water) to meet part of our summer irrigation needs and reduce the demand on our municipal water supplies!
  • By "throwing away" all this rainwater, we interfere with the natural hydrologic cycle: Instead of feeding the cycle by allowing water to infiltrate into the ground, we deprive it. This results in dehydration of the soil and the water table. Working to keep the water on your property and in the ground helps make the land and the ecosystem more resilient.
  • Creek health is also impacted by unnaturally high water flows, which cause erosion and carry pollutants from parking lots, streets and yards.
  • Harvesting rainwater can contribute to flood mitigation on both a large scale and on an individual property, as well as decrease the energy required to pump, treat and supply treated water.
  • The more rainwater we can harvest locally and the more we adapt our water "footprint" to matching local supplies, the less we have to rely on water coming to us from distant watersheds or from costly and energy-intensive sources such as desalinization.