Water use in general

It's illegal to wash your car in the street due to the pollutants from shampoos and so on that go down the drains.
It's only illegal to water plants and so on if an exceptional drought is declared.

Yes it is. The water will still wash pollutants like oil and grease into the public drains.
It's why the local car washes recycle the water and have special run off areas for the water.
Garages with pressure washers only charge a couple of euro so far better to be safe than sorry.
Water for your plants will soak into the soil and not pick up the pollutants.

It’s supposedly illegal to allow run-off from your property to flow into the public drains, so using a hose or jet wash to push dirt and debris from your property towards the street drains is also illegal.
I think the reality is that provided you act sensibly then it shouldn’t be an issue - unless you have a feud with a neighbour and they get on the phone as soon as you get the hosepipe out.

Pete.

I can't say I have actually seen many road drains in Quesada