The colour of the water in that paddling pool it looks like someone has peed in it already

Also leave it for a while open like that then see how many wiggly things are swimming in it too.
Seriously rainwater harvesting seems a good idea at the time and is very eco friendly for the types that like the thought and promote they only use harvested rainwater. However you soon reach a point it becomes pointless if you ask me once you start using more water than you can actually harvest. Then now what are the eco warriors customers going to think when they twig it was not harvested rainwater you are using after all?

I remember one year there was a hose ban in force and turned out to be the wettest year on record. Did that stop trades people using a garden hose legally?...Nope as all the water companies said to carry on as normal. Was a daft position to be in as you could turn up at a property and use their outside tap with a hose legally but they couldn't use it themselves even when it was peeing it down most of the year.
