Rain Water Collection

Being that it’s raining like it’s monsoon season here in LA, I thought I’d post some info and resources on rain water collection. So as you hear that rain falling, think of all it could be doing for us…

The basic principle uses rain gutters to re-purpose rainwater that would otherwise run down the street and onto storm drainage. This water could be used for replenishing the local water table, landscaping/gardening and home use. Your options vary from a simple barrel with a hose attached, and placed at the output of your gutters to far more advanced and costly methods. Such as the one employed by the Clovelly House which houses many interesting technologies under one roof. Read up more on their “green wall“.

As always Builditsolar has a lot of info on the subject.

But how much water can you harvest? Generally for every inch of rainfall you get .62 gallons or 2.34 liters per square foot of roof. Calculate your average rain fall (this is for my zip code, you can just put yours on the address bar). This helps when considering what size container you’ll be needing. Also be aware that some states own the rights to ALL the water and you would need to get a permit to harvest it. Colorado is an example of this. (Thanks Wikipedia)

This interesting Texas Manual on Rainwater Harvesting states some of the reasons to adopt this practice:

  • The water is free; the only cost is for collection and use.
  • The end use of harvested water is located close to the source, eliminating the need for complex and costly distribution systems.
  • Rainwater provides a water source when groundwater is unacceptable or unavailable, or it can augment limited groundwater supplies.
  • The zero hardness of rainwater helps prevent scale on appliances, extending their use; rainwater eliminates the need for a water softener and the salts added during the softening process.
  • Rainwater is sodium-free, important for persons on low-sodium diets.
  • Rainwater is superior for landscape irrigation.
  • Rainwater harvesting reduces flow to storm water drains and also reduces non-point source pollution.
  • Rainwater harvesting helps utilities reduce the summer demand peak and delay expansion of existing water treatment plants.
  • Rainwater harvesting reduces consumers’ utility bills.

If you want a long but rewarding read on the subject; check out this source book from the United Nations.