[boring rant on]
zzzzz..
Although Roman water supplies in England date back about two thousand years, and parts of them were still in use in living memory, the oldest working water supply to living accomodation I know of in the country is to the royal apartments at Hampton Court, installed around 1540.
My earlier mention of Dean Swift relates to his letter complaining about poor piped water pressure in his London home around 1710 ( I have not been able to trace this letter to check my recollection).
The great spurt in growth of piped water supply was in the Victorian era of rapid industrialisation. We still often speak of the Broad Street cholera outbreak of 1854 caused by a contaminated well.
Foreign readers will quickly grasp that English (I am not familiar with other nations' histories) water supply infrastructure and plumbing practices are very old. The pressure was low, due perhaps to the weakness of lead pipes and early valves, and the flow was slow. Accordingly it was the custom for each house to have a loft tank containing about a day's supply, that could be topped up as and when supplies and pressure were sufficient. This practice is still followed in some European and other countries where water availability is restricted.
There are still houses with lead water pipes over a hundred years old. The pressure is therefore kept lower than in countries with younger infrastrucure. These pipes are often quite small, and insufficient to deliver water at a high enough rate to fill a bath in a short time, or to run a powerful shower. In these cases a water storage tank (cistern) continues to fulfill a useful purpose.
It has always been preferred to supply drinking water direct from the mains to reduce the risk of contamination, so the cold kitchen tap is (almost) invariably supplied at high pressure. This is also why British kitchen taps are either separate, hot and cold, or of a special design which prevents the two supplies mixing inside the tap or spout. Flashy Stylish foreign taps are a frequent source of disappointment in such installations.
There's never a time when it seems convenient to turn off the water supply to forty million homes and replumb them all, and to dig up all the roads and lay new supplies, so it is being done slowly and gradually. Hence there are still homes and offices with old systems.
One of our previous governments thought it expedient to sell off our publicly-owned water industry, and much of it is now owned by offshore companies that export their profits and pay little tax.
None of this will stop overseas visitors complaining about the quaint British tap system still found in homes that have not yet had new supply pipes and internal plumbing installed.