Ralph Edward Fuhrman, 95, an environmental engineer who spent much of his career trying to clean up the Potomac River, died Sept. 30 of a stroke at his daughter's home in Villamblard, France. His primary residence was in Accokeek, but he had lived with his daughter for much of the past year.

Mr. Fuhrman first came to Washington in the late 1930s to work at the Blue Plains Sewage Treatment Plant and served as manager of the facility, which treated water for metropolitan Washington, from 1943 to 1953. He was one of the first people to speak out about the dangers of pollution in the Potomac, warning at a Senate hearing in 1950 that the river posed a "serious threat to the health and welfare of our people" and that without immediate attention, it could "become a cesspool."

Mr. Fuhrman was president of the Water Pollution Control Federation in 1950 and 1951 and served as executive director from 1955 to 1969. He edited the federation's journal from 1956 to 1964.

He was assistant director of the National Water Commission from 1969 to 1971 and was special assistant to the director of the Environmental Protection Agency's Environmental Wastewater Division in 1972 and 1973. From 1973 to 1978, he managed the Washington regional office of Black & Veatch, an international engineering company. He continued to serve as a consultant on water pollution worldwide until he was in his late seventies.

Born in Kansas City, Kan., Mr. Fuhrman received a bachelor's degree in civil engineering from the University of Kansas, a master's degree in sanitary engineering from Harvard University and, in 1954, a doctorate in environmental engineering and water resources from Johns Hopkins University. His doctoral dissertation, analyzing the water quality of the upper reaches of the Potomac, became the blueprint for the eventual cleanup of the river.

From 1931 to 1937, Mr. Fuhrman was assistant engineer of the Missouri State Board of Health and superintendent of the Water Pollution Control Plants in Springfield, Mo.

He was chairman of the executive committee of the American Society of Civil Engineers and chairman of the Wastewater Disposal Committee of the American Public Health Association. He received several awards for his contributions to improving the environmental state of waterways in Maryland, Delaware and the District.

He also wrote articles on engineering for the Macmillan Encyclopedia of Education and the Encyclopedia Britannica.

Mr. Fuhrman was a member of the Cosmos Club for more than 50 years and served on its house committee. For a quarter-century, he was the unofficial keeper of the club's clocks, applying knowledge gained from his father, a watchmaker. He was a longtime member of the National Association of Watch and Clock Collectors.

He was an accomplished sailor and owned a sailboat for many years. He also enjoyed skiing until he was in his eighties.

Mr. Fuhrman lived in Accokeek from 1939 to 1944 and, later, in Alexandria. For 48 years, he and his family lived in the Cathedral Heights neighborhood of Washington until he moved to a retirement home in Accokeek in 2001. Since 1974, he had owned a summer home in Eyrenville, France.

His wife of 68 years, Josephine Ackerman Fuhrman, died in 2003. A son, William Fuhrman, also died in 2003.

Survivors include a daughter, Anne Louise Fuhrman of Villamblard; and two grandchildren.