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Comment by mcone | Hacker News Reader

Native New Mexican here. Rainwater collection is more nuanced than this article suggests. Water that runs off a roof of a building isn't "wasted." It typically drains into an aquifer or a river. This is well-known in Tucson, a city that pumped so much groundwater that the Santa Cruz river dried up decades ago. [1]

There are also legal ramifications. In New Mexico, it's not clear whether rainwater collection is legal. [2] The water falling on your property could be somebody else's water under the doctrine of prior appropriation.

[1] https://www.tucsonweekly.com/tucson/a-river-ran-through-it/C...

[2] http://www.inkstain.net/fleck/2011/07/rainwater-harvesting-i...

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> Rainwater collection is more nuanced than this article suggests. Water that runs off a roof of a building isn't "wasted." It typically drains into an aquifer or a river.

Doesn't the article address this nuance?

"It doesn’t rain often here, but when it does it can rain very hard. And the ground doesn’t soak up water very well. So rainwater harvesting is a way to deal with stormwater runoff."

Some kinds of soil are limited in their ability to absorb water (in terms of rate). I believe these are soils with lots of clay in them. So having rainwater collection systems, though it would hurt groundwater recharge, probably on balance is better since it relieves demand on pumping out more groundwater.

Where does the article suggest the water is wasted? It seems to focus on the savings in terms of reduced demand on the municipal water plant- rainwater doesn't need to be treated- and in terms of changed behavior:

once they got that rainwater harvesting system, the way they’re irrigating is completely different, and they’re paying a lot more attention to how they irrigate. It really changes behavior. Definitely people are more careful with how they use that rainwater than how they were using the potable water to irrigate beforehand.

Certainly - the laws are messy due to the importance of water, but the amount collected in these systems tends to be trivial in the scheme of things and ends up going straight to the same ground anyway, albeit in a more distributed fashion (and one that has less runoff.)

I'd argue that it'd be in the southwest's best interest, in general, to move to clearly legalizing rainwater collection of modest amounts - say 200 gallons.

This reminds me of one of the reasons cloud seeding never took off -- what if you steal the rain of someone down wind? Imagine the liability!

Well, that and it's basically impossible to determine if cloud seeding actually works. No control group is really possible.

I just heard from someone that rainwater collection is banned in parts of Colorado. Can someone with actual knowledge comment?

It used to be illegal to do anything except direct the rainwater, e.g. direct a downspout into your flower garden. You are now allowed 2 55-gallon rain barrels.

The bummer is, even though you can now have rain barrels, it rains infrequently enough in Colorado that it's not terribly economical to buy 55-gallon rain barrels.

At $2.77 per 1,000 gallons from the utility, with infrequent rainfall it's pretty hard to ever recoup $176 for a 110 gallon system from BlueBarrelSystems. You're looking at 580 rains required to break even- while Denver, for example, sees only 40 days with "any measurable rainfall" a year.

That might be the cost of the water today, but history suggests that the price of water can fluctuate wildly. This is doubly true of the marginal cost beyond a certain baseline, which, again, fluctuates. Even without a drought or increase in regional population, you are vulnerable to (utility price, not CPI) inflation after ~5 years. The math for computing a break even period thus becomes squishy.

There are many people that place great value on being partially-off-the-grid, on (conspicuous) conservation, and enjoy DIY projects.

All good points, and certainly if you went entirely off-grid, avoiding a water tap fee is big savings. Though, 110 gallons isn't going to get you very far if you're totally off-grid.

It's basically because someone else might be using that water. So in the same way that if a creek is on your property in most states you probably aren't allowed to just siphon it all off to water your corn.

http://water.state.co.us/SurfaceWater/RainwaterCollection/Pa...

> 110 gallons of precipitation [...] can be collected and stored

With additional restrictions.

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