As this Thread is useful Tips - I am putting one about domestic water. I am registered on Thames Water 'WaterSure' scheme. This is a special scheme for those who have certain on-going medical conditions which require perhaps more water than most people.
I have been on this for some years, - you do have to provide appropriate medical prove - although it states it gives me aid towards my water bills - that on kicks in at a certain expediture level which, thankfully, I have never reached.
However, a week ago a ring at my doorbell and there was a lady from Thames Water checking up on me as there had been a mains burst in my area and a couple of times some streets had been without any water for a few hours. Fortunately, it had not affected me. However, she was calling on all registered WaterSure users in the area to check we were okay, insisted on giving me a pack of six large 'Courtesy' bottles of water, and told me that if I ever had any problems about water,, just to phone them and they would have someone around to ensure I had an adequate supply for my needs.