Documentary History of American Water-works

Units of Water Measurement

| Meters | Per Capita Water Consumption | Water Rates |

Water systems used several units to measure water consumption in the early Nineteenth Century.  Philadelphia used ale gallons containing 282 cubic inches until 1855.  New York City used imperial gallons of 277.42 cubic inches, even though New York State had in 1829 defined its own gallon unit as containing eight pounds of distilled water, or 221.184 cubic inches.

The United States Treasury Department in 1836 adopted the wine gallon as the standard liquid measure, which contained 231 cubic inches, but this too some time to catch on in the various states.  A cubic foot contains 1,728 cubic inches or roughly 7.48 gallons, (more exactly 7.480519481... ).  The Boston water works rounded this off to 7.5 gallons per cubic foot, or 230.4 cubic inches.  Today the US liquid gallon is legally defined as 231 cubic inches, which is exactly 3.785411784 liters.

American water systems still measure and bill for water consumption using either gallons or cubic feet, which makes it difficult to compare water rates.  In countries using the SI system, one cubic meter is equal to 1,000 liters, but it is not known if any water works in the United States uses the SI system.

Water works pumping engines and system capacity are usually expressed in million gallons per day, or MGD.

Irrigation systems use the acre-foot, which is defined as volume of one acre of surface area to a depth of one foot, equal to 43,560 cubic feet, 75,271,680 cubic inches, or  325,853.4 U.S. gallons (rounded off).

In the Western states, the Miner's Inch was commonly used to measure water flow.  It is derived from the amount of water that would flow through the hole of a given area at a given pressure, and had different definitions in different locales. 

A few early water systems measured storage in barrels and flow in barrels per hour or day, but with no universally-accepted definition of a barrel of water such references need to be clarified as much as possible.

References
1787 Constitution of the United States
Article 1, section 8, paragraph 5 authorizes Congress to "fix the standards of weights and measures."

1829 New York.  An act concerning Standard Measures of Capacity. April 29, 1829.
§3. The gallon for liquids, shall be a vessel of such capacity as to contain at the measure pressure of the atmosphere, at the level of the sea, eight pounds of distilled water at its maximum density.

1834 Pennsylvania.  An act to fix the Standards of Measures and Weights in the Commonwealth of Pennsylvania,  April 15, 1834
P.L. 524 sec 2  The standard of liquid measure shall be the gallon to contain two hundred and thirty-one cubic inches.

1836 U.S. Congress Joint Resolution No. 7. Distribution of Weights and Measures. A resolution providing for the distribution of weights and measures. June 14, 1836.

1851 New York.  An act in relation to weights and measures.  April 11, 1851.
§1.  One set of standard liquid capacity measures, consisting of one wine gallon of two hundred and thirty-one cubic inches.
§8.  The units or standards of measure of capacity for liquids, from which all other measures of liquids shall be derived and ascertained, shall be the standard gallon and its parts, designated in the first section of this act.
§9.  The barrel shall be equal to thirty-one and a half gallons, and two barrels shall constitute a hogshead.

1851 Report of the Cochituate Water Board, January 15, 1852.
Page 88:  The standard of measure adopted by the Boston Water works, is not precisely the wine gallon, but is exactly two fifteenths of a cubic foot, so that in order to reduce the gallons in the foregoing statement to cubic feet, it is only necessary to divide by 7½.  It is to be regretted that there is not some common unit of measure on all the Water Works throughout our country; as it is, New York had adopted the Imperial gallon, Philadelphia, the Ale gallon, and Boston, the Wine gallon. [One wine gallon equals 7.48 cubic feet.]

1855 Annual Report of the Chief Engineer of the Water Department of the City of Philadelphia, January 17, 1856
Page 5:  At the time the works at Fairmount were erected, the standard measure of water was the ale gallon of two hundred and eighty-two cubic inches; but as nearly all the water works of the country now use the wine gallon of two hundred and thirty-one cubic inches, and as it had heretofore been used by some of the steam works now under my charge, I have concluded to make the latter the basis of calculations hereafter, or at least until the United States government gives us an actual standard gallon.

1857 Report of the Secretary of the Treasury on the Construction and Distribution of Weights and Measures, 34th Congress 3d Session, Ex. Doc. No. 27

1893 Bulletin No. 26 – Fundamental Standards of Length and Mass. United States Coast and Geodetic Survey, Treasury Department, April 5, 1893.  Reprinted in Appendix 3 of 1976 reference below.

1904 Laws Concerning the Weights and Measures of the United States, First Edition

1912 State and National Laws Concerning the Weights and Measures of the United States, Second Edition

1926 Federal and State Laws relating to Weights and Measures, Third Edition, August, 1926

1958 The Federal Basis for Weights and Measures: A Historical Review of Federal Legislative Effort, Statutes, and Administrative Action in the Field of Weights and Measures in the United States, National Bureau of Standards Circular 593, June 5, 1958.

1976  Weights and Measures Standards of the United States: A brief history, National Bureau of Standards Special Publication 447, by Louis E. Barbrow and Lewis V. Judson

© 2020 Morris A. Pierce