FRISCO — Conservation advocates say a proposed law to legalize limited backyard rainwater collection could build more widespread appreciation for one of Colorado’s most important resources.
HB 15-1259 would allow people to use up to two 50-gallon barrels to capture rainwater falling on residential properties and use it for outdoor irrigation. As currently written, the law would enable people to catch about 600 gallons of water per year, enough to water about a dozen tomato plants during the growing season.
That may not seem like a big deal, but it’s currently illegal under Colorado’s frontier-era water laws, which include the fundamental premise that every drop of rain needs to flow back into a river or into the groundwater, where it becomes part of a downstream water right owned by someone else who previously claimed it.
“When we talk about this, most people’s reaction is, ‘What, you can’t do that already?’” said Becky Long, a water expert with Conservation Colorado. She described the rain-barrel bill as a “gateway drug” for water awareness and conservation.
“We think there are a lot of people doing this already,” Long said. Even though capturing rainwater is technically illegal for most people, there’s never been a meaningful effort to enforce it since state officials don’t have the resources to chase down thousands of rainwater renegades, she said.
Enabling people to use rainwater for their petunias and sweet peas would stimulate water awareness, helping to shift the common mindset that water is automatically available in endless quantities whenever you turn on the faucet, she explained.
The state last grappled with the issue of rainwater capture in 2009, when a slight change to regulations enabled only rural residents with well permits to use captured rainwater on a limited basis. Even that tiny tweak spurred concerns about potentially undermining the state’s prior appropriation doctrine by diverting water that has already been claimed by somebody else.
But the reality is that very little of the water — about 3 percent — that falls as rain on landscaped residential areas ever makes it back to a stream or river. Recent studies show most of the rain is used on the spot by plants growing near gutters and downspouts. That means it’s unlikely any downstream water user’s rights would be affected by small-scale collection of rainwater.
After crunching some numbers on average roof sizes and rainfall, conservation advocates estimate that the two 50-gallon barrels could only capture about 6 percent of the total amount of rain that falls on an average home.
To help people understand the effect of the proposed law, Western Resource Advocates calculated that, if half of Denver Water’s 300,000 residential customers used rain barrels, they could capture about 90 million gallons per year. That’s about 275 acre-feet, enough water for about 275 average households for a year.
“We think that if people were allowed to use rain barrels they’d become more water-smart citizens, paying closer attention to how much water they’re using indoors and out,” said Drew Beckwith, a water expert with the group. “Ultimately, that leads to better decision making, less urban demand and more water in rivers.”
At this stage, there doesn’t seem to be any active opposition to the measure, and Denver Water even offered a qualified statement of support.
“Denver Water supports innovative ways to maximize the use of local water supplies and use water more efficiently,” said Jim Lochhead, CEO and manager of Colorado’s biggest water provider. “This legislation reflects the type of thinking we will need to make our cities more resilient.”
Rain barrels are already commonly used in some dry areas, including San Diego, Santa Fe, Austin and Tucson, which all give financial incentives and rebates for installing residential rain barrel systems because it relieves some of the pressure on municipal water providers. Utah also passed a statewide measure to allow the limited use of residential rain barrels. But none of those places applies the “prior appropriation doctrine” as strictly as does Colorado.
Some people just use a big extra garbage can under a downspout to catch the water, along with a smaller bucket or watering can to apply it to their gardens. Retailers like Home Depot already sell specialized barrels with a built-in spigot for between $100 and $200.
Backers of the new law say it wouldn’t have a big financial impact. Based on average water rates and usage, utilities might end up collecting about $2 less per year from their residential customers. The bill is set for a March 16 hearing at the House Ag committee.[ Top photo by Bob Berwyn; rain barrel courtesy Conservation Colorado.]