Humming water pipes are more than an annoyance---they are also a symptom of underlying plumbing problems. Finding the hum's cause and eliminating it can extend the life of plumbing fixtures and appliances.
Excessive water pressure often generates harmonic vibrations in pipes, resulting in humming and other noises. According to the International and Uniform Plumbing Codes Handbook, pressures of 18.1 to 22.7 Kilogram per square inch (psi) are generally sufficient for home use.
Imperfect seals resulting from loose or worn-out washers can also produce a humming sound. Washers in faucets and toilet valves are frequent culprits.
Sound can travel far in water pipes, so humming may occur at a distance from its source.
Maintaining home water pressure at or below 60 psi can prevent or eliminate humming noises in pipes. Replace the water pressure regulator if it cannot keep the pressure in check. If humming occurs during operation of a particular sink or toilet, replace faucet washers or toilet flush and refill valve washers.
Excessive water pressure places strain on fixtures and appliances designed for lower pressures and can cause supply lines or valves to rupture.