[lelandfe]

I can sorta kinda dream up a reason for solar rules to exist. Not good ones, mind.

But can anyone take Devil’s advocate here and explain why a state might want to limit or prohibit rainwater collection? I’m struggling.

Surely it can’t just be financially motivated, right?

[gpas]

You collect a couple of gallons of rainwater, no problem. Everyone upstream catches rainwater? After all it's unregulated, a tank or a pond, no difference. Now cities downstream have no water.

[kwhitefoot]

Collecting rainwater disturbs the flow of water to downstream users.

[amanaplanacanal]

This is the real answer. In some cases that water is already owned by someone downstream.

Here is the scenario: you are the first settler in an area. You settle by a stream and use the water for irrigation or whatever. Then someone settles upstream from you and diverts the water for another use. In many places you have property rights to the flow of that stream based on prior usage.

[denton-scratch]

> that water is already owned

Yup. If you allow people to "own" rainwater that hasn't even fallen yet, you are going to need some batshit regulations. So don't do that then.

[18pfsmt]

Water rights have long been an issue in the mountain west, and are highly coveted. They go back to the settling of areas, and directly influence property values. Even well-depth is regulated for newer properties so as to prevent them from usurping water in use by existing residents.

[liamwire]

I can see replenishment of the water tables being a concern, if everyone (or a good percentage, at least) started doing so. Add to that concerns about disrupting existing ecosystems, and I could see at least a partway compelling case that could be made. In fairness, there are likely to be at least an equal number of counter arguments that could be levied as well, but such is the nature of governance.

[Scoundreller]

Are there any reported cases of water tables dropping because of residential water use? I always see agricultural and out-of-home use blamed (e.g. large lawns/gardens). I mean, any draw has impact, but I imagine water tables being so full of water when you hit them that you 100L/day draw for showers/cooking/washing/flushing has insignificant impact in any non-urban area.

[pbhjpbhj]

>can see replenishment of the water tables being a concern, if everyone (or a good percentage, at least) started doing so.

Used to live in a village with a well (acquifer) and pumping station but in the city I live in now, and all the surrounding towns, all the water supply comes from rainwater (via a reservoir and treatment plant) ... like, where else you going to get it from?

[ghaff]

Well, desalination notwithstanding, pretty much all water people use comes from rainfall/snowfall. It's just a matter of what combination of aquifers, man-made reservoirs, lakes, rivers, etc. are used to manage the water supply.

[pkaye]

If a lot of it in diverted it might disrupt the ecosystem of ponds and streams that existed.

[denton-scratch]

> why a state might want to limit or prohibit rainwater collection

It seems nuts to me - a bit like regulating the breathing of air, or restricting the right to look at the sky.

I can only suppose that these regulations protect the revenue of water companies. I can't think of any socially-useful reason for restricting rainwater harvesting, when the rain is falling on private property.

Harvesting all the rain that falls on a floodplain is another matter; that would amount to appropriating an entire river, which in some parts of the world would cause an "international incident".

[tonyedgecombe]

I suppose you could argue from a health perspective, you don’t want half arsed systems that lead to people getting cholera.