You probably know about this, in which case, excuse me.
I have helped just 3 people to reduce their water bills. It's not advice on saving water, it's discounts for eligible people.
Each time it took one, no waiting phone call.
This site will take you to your water company and explain the savings:
Matin Lewis watersure scheme.
I'm sorry I cannot link. It's worth a google for yourself and anyone you know who might benefit.