Municipal water systems and water companies generally provide enough pressure from pumps and / or water stored at higher elevation or in an air pressurized storage tanks.

Taller buildings have to have their own pumps and occasionally tanks to lift and pressurize at higher elevations.

Water systems with extensive change of elevation typically have pressure reducing valves that isolate higher elevations from the lower elevation portions of the system so that the force of gravity doesn't overpressurize lower elevations and rupture pipes, and also have valves so that leaks in lower elevations don't dewater higher elevations, creating such an aggressive siphon as to implode water heaters and other tanks at higher elevations.