Los Angeles May Get Mandatory Rainwater Harvesting Law


Photo via gilintx via Flickr CC

A new proposed law to go into effect in 2011 could have Los Angeles residents changing their habits when it comes to rainfall. Rather than just complaining that there's some strange wet substance falling from the sky, all new homes, large developments, and some redevelopment projects will start to appreciate those few rainy days by harvesting and redirecting rainfall. The Department of Public Works has unanimously approved the new ordinance that will require the use of several different methods to capture, reuse or redirect runoff from 3/4 inch or heavier rainstorms. Does this mean LA is becoming water wise? Ecolocalizer reports, "Not only will Los Angeles' new ordinance help to recycle our planet's most precious resource, it will also help to keep polluted urban water out of our increasingly acidic seas. The Board of Public Works Commissioner Paula Daniels, who initially drafted the ordinance last July, explained that the new requirements would prevent over 104 million gallons of polluted urban runoff from ending up in the ocean."

This is very true, but this aspect of rainwater harvesting isn't as beneficial as making other, much larger and more expensive yet important changes - making LA's surfaces more permeable so that rainwater can filter back down to the groundwater table. One of the main reasons polluted water heads to the oceans is that it lands on concrete and pavement, then rushes straight into storm drains that lead to the ocean. It never has a chance to trickle down and replenish the groundwater supply. Making the city surfaces more permeable is an infrastructural change that has to be considered as seriously as rainwater harvesting.

Thankfully this isn't being ignored in the proposed law:

"In addition to encouraging the use of rain storage tanks, builders would be required to use other low-cost and sensible water management methods; these include simple measures, like diverting rainfall to gardens, constructed infiltration swales, mulch and permeable pavement, all of which will help to sustainably direct the rain directly where it falls. Any builders who are unable to manage 100% of a project's runoff on-site would be required to pay a penalty of $13 a gallon for the water that is not safely redirected. This fee will help to fund sustainable off-site water management projects."

WATCH VIDEO: Renovation Nation: Harvesting Rainwater

Not everyone is ecstatic about the idea. The LA Times reports that some building projects in areas where the soil is high in clay are going to have a tough time with the 100% retention rule. A one-acre building on ground where runoff could not be managed on site could see fees as high as $238,000.

"The Building Industry Assn. is supportive of the concept of low-impact development and has invested a lot of time and energy in educating our members on those techniques and advancing those technologies," said Holly Schroeder, executive officer of the L.A.-Ventura County chapter of the association. "But when we now start talking about using LIDs as a regulatory tool, we need to make sure we devise a regulation that can be implemented successfully."

However, there are solutions for every problem - even clay-dense soil.

Los Angeles could also benefit from improved water management in the first place - all those lawns and swimming pools aren't doing much to help alleviate water woes. But going the route of rainwater harvesting and diversion is a much better solution than launching a new energy intensive desalination plant. We're hoping the law goes though, and it sees success.

Follow Jaymi on Twitter: @JaymiHeimbuch
More on Los Angeles and Rainwater
Alternative Builders Search for Solutions in Southern California
Los Angeles Approves Plan to Seed Clouds for Rain with Silver Iodide
California Drought Means Thousands of Trees to be Cut Down

Tags: California | Drinking Water | Los Angeles | Water Crisis

Best of TreeHugger