The Rainwater Paradox

Garden irrigated by rainwater
A thriving rainwater garden…

Los Angeles is a paradox. Our two defining water infrastructures essentially perform opposing tasks. The aqueduct system imports water from far  away at a staggering environmental cost, while the Los Angeles River is a concrete channel designed to move rainwater as efficiently as possible out of our city into the ocean. Think about it: we import water hundreds of miles over mountain ranges only to dump any locally available water into the ocean as quickly as possible!

So, does it make sense to capture rainwater in Los Angeles? Absolutely! Due to the large area of a typical collection surface (i.e., a roof), it doesn’t take much rain to generate a lot of water. One inch of rain falling on a 1,000 square foot roof adds up to 600 gallons! And the yearly average rainfall in L.A. is 15 inches.

15 inches of rain on that small roof could yield around 10,000 gallons of pure, clean rainwater – if you had the storage capacity to capture it. That’s why we generally recommend that people go large. A few 50 gallon barrels scattered around the property are nice, but they will rapidly fill up and overflow with only a minor shower.

Rainwater tank and pump
…and the storage system that supports it!

Types of Rainwater Systems

Rainwater harvesting doesn’t have to be complicated – simply diverting water from downspouts to nearby tanks will do the trick.

However, system size is important. 50 gallon barrels are cute but ineffective – they fill up almost instantly and you use them in a day. When the rain does come in Southern California it is usually an inch or two over a few days, which will produce hundreds or even thousands of gallons on even a moderate size roof. We work with a range of rainwater tank providers to provide solutions that fit each job, from massive underground underground cisterns to small-footprint “slimline” tanks for tighter lots.

We custom-design each system to fit the site and owner’s needs. Sometimes a simple gravity flow system will do the trick. Other times we can incorporate pumps and multiple storage tanks as needed. More complicated rainwater harvesting systems can involve advanced pre-filtration and purification of rainwater.


modular rainwater tank
Modular tanks allow for large underground capacity at small or irregular sites.

Rainwater comes with many advantages, including the following facts:

  • It is free.
  • It is clean, meaning you can use it for drip irrigation and store it in tanks with minimal treatment.
  • Existing irrigation systems, and even greywater systems, can use rainwater.
  • Rainwater is good for long term storage.
  • It can supplement existing irrigation, or sustain native plants with zero additional water.
  • If water lines fail it can provide emergency water.

Get your own system

Each project is unique, so we start with a phone call or email exchange to learn about your needs and discuss the best type of system for your situation. We are more than happy to talk about your options and find a system tailored to your needs. So… CLICK HERE TO GET STARTED RIGHT AWAY!

"Slimline" compact high-capacity rainwater tank
“Slimline” rainwater tank: large capacity, small footprint.

The Greywater Corps Guarantee

We stand by all of our installations by offering repair and maintenance services at any time. We aim to build relationships that last as long as our systems do!

Furthermore, we guarantee to meet the highest standards of work both outside and inside of your home. We are licensed contractors and architects with nearly a decade of experience building these systems. When we are done, everything will look the same except for your water bill. Our greywater systems are practically invisible except for the results: a thriving, beautiful, sustainable oasis!