The Rio Arriba County Assessor found an error in 2025 property tax rates that would have cost property owners in Rio Arriba, Taos and Santa Fe counties more than $2 million.
The error was in the mill levy rate for those in the Northern New Mexico College special tax district, which includes the entirety of Rio Arriba County and parts of Taos and Santa Fe.
County Assessor Joaquin Valdez discovered the error in his standard annual review of the property tax rates before they went to the Rio Arriba County Commission for approval.
He noticed an issue with the mill levy rate for NNMC right away because it was higher than a rate approved by voters six years ago.
“In 2019, (for NNMC), there was a question on the General Election if NNMC could have an operating mill levy of two mills per every $1,000 of valuation, so it could not increase more than two mills,” Valdez said in a telephone interview. “When we got the tax rate and I saw that the residential rate was showing a rate of 3.468 and the non-residential rate was five, that made me think, ‘Well, that’s not accurate.’”
Mill levy taxes are rates imposed on a person’s property by local governments or voters. In New Mexico, counties and cities can increase mill levy rates without voter approval to pay off principal and interest on debt. Voters can approve mill levy tax increases for things like maintenance, technology, roads and other capital improvement projects.
Properties are taxed on one-third of its total value, which means if the county assessor determines it is valued at $300,000, the owner only pays taxes on $100,000. Each mill is equal to $1 for every $1,000 of valuation.
The county received the revised tax rates for 2025 in August, which are provided by the New Mexico Department of Finance and Administration, which compiles them using data from municipalities, counties and departments across the state.
The mistake originated from the New Mexico Higher Education Department, which regulates public colleges and universities and for-profit private institutions of higher learning.
The Education Department provided the Department of Finance and Administration with the mill levy rate for New Mexico Junior College in Hobbs.
If Valdez had not caught the error, residential properties would have been taxed at 3.468 mills instead of 1.891, which would have caused owners to overpay by about $1.58 more for each $1,000 of their property’s value.
Non-residential properties would have been taxed at 5 mills, or about $3.11 more per $1,000 of value.
After he found the error, Valdez spoke with Cordelia Chavez, the Budget and Finance Bureau Chief at the Department of Finance and Administration, who confirmed the error.
In total, property owners would have paid $2,457,533 in undue taxes.
Since the NNMC tax district extends into parts of Taos and Santa Fe counties, Valdez began working with those county commissions, along with the Department of Finance and Administration to correct the error.
The Taos County Commission had already passed the tax certificate with the incorrect rate and had to reopen their meeting to correct the mistake. Similarly, the assessor for Santa Fe County amended its tax rate with the incorrect numbers, and also had to go back and fix them, Valdez said.
“At the end of the day, the Northern New Mexico College mill levy ended up going down,” Valdez said. “It went from an increase of 80 percent to a decrease of almost 2%.”