I am planning to supply drinking water only (not bath or sanitation or washing) from a tank on a 10-storey building.

The problem is that if a gravity feed is used, then the pressure will be different on each floor. For example, the estimated PSI will be only 7 on the top floor and 46 on the bottom. Ideally we want to have a PSI of 40 PSI on every floor. How can this be accomplished?

  • 1
    $\begingroup$ You will have to pressurise the water supply to the upper floors and regulate the pressure for the lower floors... $\endgroup$
    – Solar Mike
    Oct 2, 2017 at 15:55
  • $\begingroup$ Why do you need 40 PSI for a drinking water supply? In the UK, cold drinking water taps are often connected straight into to the mains supply, not via a header tank. The legal minimum water supply pressure to a building is only 10 PSI in the underground pipe, and therefore less than 10 at "tap level" on the ground floor - not 40. 10 PSI is enough pressure to supply a liter of drinking water in about 5 seconds - do you really need it faster than that? $\endgroup$
    – alephzero
    Oct 2, 2017 at 21:59
  • $\begingroup$ @alephzero In the United States, 20 PSI is the minimum legal house water pressure, and 50 PSI is the recommended house pressure. The typical house has faucet pressure of 30-40 PSI. For a drinking water spigot 40 is a good pressure. $\endgroup$ Oct 2, 2017 at 23:24
  • $\begingroup$ @alephzero - To reduce the flow rate, we put in flow regulators. The high pressure is useful for running the water machinery (such as dishwashers, washing machines, etc), and more importantly for showers. $\endgroup$
    – Mark
    Oct 3, 2017 at 13:41

1 Answer 1


The best method is to pressurize your tank on the upper floor, then regulate the flow as it goes down. This is because pressurizing will require active components (i.e. pumps, and other devices that you do not want to run continuously, or they will cost money while not in use). Once the tank has 40 psi of pressure, a water pressure regulator at each floor, such as shown below, should be used:

enter image description here

One of these at each floor can trim the pressure properly to the correct pressure.


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