Hi all, I have a physic question about water pressure in high rise residential building.
In condition that the central water storage tank on top of the building and all floors share one water supply pipe, common sense as we know: lower floor would get higher water pressure.
But I am not sure if plenty of floors opened water tap at the same time, as I can imagine the higher floor is nearer to the top water tank compared with lower floor, and higher floor would get the water supply earlier, does this mean that higher floor could have higher water pressure compared with lower floor in this case?

Thank you.

Assuming no water pump installed at the tank, higher floor will get lower water pressure if alot of the lower units are consuming water at the same time

Have personally experienced this in one of the condo I rented before

The further from the water tank on the top, the higher the pressure.

There are high rise that installed booster pump for the top 2 or 3 floors, as water pressure may be too low, as the height between the floor and water tank is not enough to create the adequate pressure.

While for lower/lowest floor, it may be need to install pressure regulator or pressure reducer, as the pressure may be too great.

Probably a poor job done by contractor in case of johnseamus

If the building is high, the lower units water pressure can be too much that it cannot be handles by standard fixtures. Just like normal water distribution to residential areas that have different elevation, every several floors they will install the pressure reducer so that no matter what floor you stay on, the pressure are distributed equally.

Even if the apartment is using pump on ground floor with tank on ground level as well, the pressure are still regulated with reducer to ensure even pressure distribution of pressure. Otherwise, units at the end of the pipe line will always suffer low pressure

The central tank usually has an air pump to pressurize the tank.