Rain barrels are in the news again in Colorado, the only state in the US where collection of rainwater is illegal. House Bill 1005, now with the Senate, is an attempt to change that; a similar bill was defeated last year.
Many people react strongly to this debate with a question: why is rainwater capture, a strategy that seems aligned with a water conservation ethic, still illegal in a dry state that needs to conserve water?
Others answer just as strongly that the longstanding and tightly managed “prior appropriation” system of Western water rights must be protected. Once the spigot on rain barrels has been opened, can it be turned back off if water rights owners are affected?
Those two poles sum up most of the discourse around this issue, and those viewpoints tend to be religiously laid out in media coverage of the bill. Still, the bottom of the barrel remains murky. What are some of the nuances being carefully considered behind the scenes?
- Rainwater harvesting has actually been legal on a limited basis in Colorado since 2009, when a law enabled people who couldn’t physically connect to a municipal system to collect rainwater from the roofs of their houses and use it on their property for whatever purpose their well permit allowed them to use water for. How many people are operating in this capacity? Has there been evidence of injury to water rights from this law?
- In urban areas, residential development means impervious surfaces like streets and roads funnel rain not into the ground, but into municipal water treatment systems or storm drains that dump into rivers. Does this mean that rain water that would be collected in cities isn’t available to streams for diversion by water rights holders anyway? Much of the water used for municipal supply comes from rural areas. If rainwater harvesting catches on in these areas, how would water rights in big drainages be affected by changing the current storage dynamic of rainwater?
- In times of low or even average river flows, some water right holders have to place “calls” on their water source that halt junior diversions so the senior rights can get their allotted water. Water rights can be expensive to maintain, and are the lifeblood of many family farming operations and even municipal supply. Just how tenuous is this balance? Is it really so tight that rainwater harvesting could have an impact and immediately cause some rights holders to be denied water? If so, where does this happen and what’s the recourse for the longtime water right holder?
- Other Western states have managed to uphold the prior appropriation doctrine while allowing rainwater harvesting. However, Colorado is a headwater state for the six states dependent on Colorado River water, and at the same time, it’s the only mainland state that has rivers flowing out but no rivers flowing in. All of Colorado’s water comes from snowpack and rain. Could the scale of rooftop water harvesting become big enough to impact the water legally promised to other states? A 2007 study (that helped the 2009 law pass) found that 97 percent of rain in one Colorado county evaporated or was taken up by plants – it didn’t even make it from the clouds to the ground. But that is one county in a state with diverse topography and microclimates. How does this dynamic work in every area that is crucial to stream flows?
- Coloradans can accomplish the same things rainwater harvesting does with two other legal methods: piling snow on lawns, and building rain gardens or bioswales in landscaping. Bioswales are designed primarily to clean silt and pollution from runoff, but like rain gardens, they’re depressions in the soil that can hold excess water in times of plenty, slowing and directing its absorption into soil. Coloradans get much more precipitation as snow than they do as rain, and stockpiling snow on one’s lawn or deck isn’t against the law; if rain’s delay back into the system is long, snow’s has got to be longer. If these two strategies don’t raise concern over prior appropriation harm, why does rainwater collection do so?
- Some people have been capturing rainwater illegally for years in Colorado. In other states, rainwater capture is only used by 5 to 10 percent of households; how does Colorado currently compare to this number, and will it reach the same plateau of adoption?
- How is marijuana cultivation affected? The bill’s current wording allows “outdoor” use of collected rainwater, which include large, warehouse sized greenhouses (large roofs included), though due to strict state regulations, major marijuana growing operations are usually not located outdoors on a residential lot.
- In the language of the bill, rooftop snow accumulation is equivalent to rain under the generic term, “precipitation.” Snow piles up in winter and early spring; rain comes in late spring and summer if at all. How much weight does the seasonality of these flows have in the debate? How does this affect water right holders who expect injury – are they most concerned with summer flows or spring?
The sponsors of this bill hope to encourage water-wise practices that are imperative in an arid region with ever-growing water demand. The bill even stipulates that an HOA may not prohibit the use of rain barrels, so the intent is to boost adoption as much as possible. Water rights holders are acutely aware of the value of water and understand the importance of conservation, but they are looking for assurance that if the practice becomes more widespread in Colorado, their water availability and their long-fought-for rights won’t be harmed. After amendments added Monday that address data collection on impacts, provide for a review and objection period in the future, and expressly stipulate that rain water harvesting does not constitute a water right, it looks like the bill may pass this time.
Take a closer look at the issue and you’ll realize it isn’t as simple as saying this argument has pitted conservationists versus the old farming lobby. Water rights are an important component in our state’s laws, and affect flows that underpin a broad spectrum of critical water uses, stream conservation, farming, and municipal supply, among others. They are inherently tied to our economy and ability to grow sustainably. Asking the less obvious questions is always more likely to lead us to a solution we can all live with.