| Williamstown - Property Tax Rates | FIPS Code=17085 |
| Year | Effective Tax Rate |
| 1970 | 2.17 |
| 1972 | 2.09 |
| 1974 | 2.46 |
| 1978 | 2.12 |
| Year | Effective Tax Rate | Municipal Tax Rate | School Tax Rate | |
| 1980 | 2.29 | 0.54 | 1.75 | |
| 1982 | 1.83 | 0.50 | 1.33 | |
| 1983 | 2.03 | Not Available | Not Available | |
| 1985 | 2.27 | Not Available | Not Available | |
| 1987 | 2.29 | Not Available | Not Available | |
| 1988 | 2.04 | 0.63 | 1.41 | |
| 1989 | 2.00 | 0.59 | 1.41 |
| Year | Effective Tax Rate | Municipal Tax Rate | School Tax Rate |
| 1990 | 1.79 | 0.53 | 1.26 |
| 1991 | 1.64 | 0.48 | 1.16 |
| 1993 | 1.76 | 0.54 | 1.22 |
| 1995 | 1.80 | 0.46 | 1.34 |
| 1997 | 2.04 | 0.53 | 1.51 |