August 2, 1911: Municipal Journal article. Water Waste in Washington, DC. “The matter of detecting and closing underground leaks in the distribution system is one that the water department of Washington has been working on systematically and rather extensively since 1906.
At that time the rapid increase in both mean consumption and per capita rates made it quite evident that unless radical measures were taken the city would soon be face to face with at least a partial water famine; the increasing danger had been recognized for years, but shortage of funds and the failure of Congress to authorize the general installation of meters had prevented taking up the work on an effective scale.
The per capita rate, based on the entire population, was 169 in 1896 and 217 in 1906, while the mean daily rates for the two years were 44,500,000 and 67,500,000 respectively. During a short period of unusual cold in the winter of 1904-5 the consumption exceeded the capacity of the conduit supplying the city, and the local reservoirs were drawn down close to the danger line. Before the trouble reached the consumer the weather moderated, and conditions again became normal.
Among several means used to decrease the great waste of water was the systematic search for and repair of such underground leaks as showed no evidence on the surface….
The principal instruments used in the work are the pitometer and the aqua phone; the former, as is well known, being a device by means of which the velocity of flow at any point in a main may be determined readily and without undue expense, and the latter an instrument resembling a telephone receiver, by means of which the sound of water escaping under pressure from a leak, flowing through a service pipe or through a partially opened valve may be detected.