Community water fluoridation began in the 1940s. Since then the number of community water systems and the number of people served by fluoridated systems have been steadily increasing. Currently about two-thirds of the US population receives fluoride through their community water system. This has been an important factor in the steady decrease in tooth decay rates.
| Year | Receiving Fluoridated Water - Natural | Receiving Fluoridated Water - Adjusted | Receiving Fluoridated Water - Total | Served by Community Water Systems | Total U.S. Population | Percentage of U.S. population receiving fluoridated water* | Percentage of population served by community water systems receiving fluoridated water |
2002 | | | 170,321,020 | 253,104,805 | 288,600,000 | 59 | 87.7 | | 2000 | | | 162,067,341 | 246,120,616 | 282,434,000 | 57.4 | 87.1 |
| 1992 | 10,011,861 | 134,657,132 | 144,217,476 | 232,438,000 | 256,894,000 | 56.1 | 90.5 |
| 1990 | | | | | 250,132,000 | | |
| 1989 | | | 135,256,757 | 220,179,000 | 247,342,000 | 54.7 | 89 |
| 1988 | | | 132,422,064 | 218,924,000 | 245,021,000 | 54 | 89.3 |
| 1985 | | | 130,172,334 | 211,730,873 | 238,466,000 | 54.6 | 88.8 |
| 1980 | | | 115,948,946 | | 227,726,000 | 50.9 | |
| 1975 | | | 105,338,343 | | 215,973,000 | 48.8 | |
| 1970 | | | | | 205,052,000 | | |
| 1969 | 8,378,824 | 80,096,860 | 88,475,684 | | 202,677,000 | 43.7 | |
| 1967 | 10,009,000 | 71,916,700 | 81,925,700 | | 198,712,000 | 41.2 | |
| 1964 | 7,706,000 | 48,363,100 | 56,069,100 | 150,277,000 | 191,889,000 | 29.2 | 78.3 |
| 1963 | | 46,678,380 | | | 189,242,000 | 24.7 | |
| 1962 | | 44,045,392 | | | 186,538,000 | 23.6 | |
| 1961 | | 42,201,115 | | | 183,691,000 | 23 | |
| 1960 | | 41,179,694 | | | 180,671,000 | 22.8 | |
| 1959 | | 39,628,377 | | | 177,830,000 | 22.3 | |
| 1958 | | 38,461,589 | | | 174,882,000 | 22 | |
| 1957 | | 36,215,208 | | | 171,984,000 | 21.1 | |
| 1956 | | 33,905,474 | | | 168,903,000 | 20.1 | |
| 1955 | | 26,278,820 | | | 165,931,000 | 15.8 | |
| 1954 | | 22,336,884 | | | 163,026,000 | 13.7 | |
| 1953 | | 17,666,339 | | | 160,184,000 | 11 | |
| 1952 | | 13,875,005 | | | 157,553,000 | 8.8 | |
| 1951 | | 5,079,321 | | | 154,878,000 | 3.3 | |
| 1950 | | 1,578,578 | | | 152,271,000 | | |
| 1949 | | 1,062,779 | | | 149,188,000 | | |
| 1948 | | 581,683 | | | 146,631,000 | | |
| 1947 | | 458,748 | | | 144,126,000 | | |
| 1946 | | 332,467 | | | 141,389,000 | | |
| 1945 | | 231,920 | | | 139,928,000 | | |
| 1940 | | | | | 132,122,000 | | |
Source: Centers for Disease Control and Prevention 2002 Water Fluoridation Reporting System (WFRS)