The answers you've received have been good. You cannot assume that there's any relationship between the assessment of a particular property and its fair market value.

Having said that, I just (yesterday) did some research on that subject. I looked at a number of Northern Virginia communities (Greenbriar, Winter Hill, Hampton Court, and a few others). I looked at the average net sales price in those communities (sale price minus any seller incentives). Then I looked at 5-10 recent sales closest to that average. I then looked at those assessments.

In Greenbriar, for instance, the average net was $354,170. I took a look at 8 sales that were closest to that number. Those averaged out to $349,875. (My intent was to eliminate the outliers--the ones that had been overimproved and the foreclosures.) Then I looked at the tax assessments for those 8 houses. The average: $350,070. So the tax assessments, as a group, were almost precisely on target with the actual values.

For Winter Hill, the average net was $307,625. The average assessment for 4 sales closest to that figure was $323,650, about 5% off. For Hampton Court, there was about a 4% spread.

So, to give Fairfax County a bit of credit, at least in the communities I looked at the aggregate assessments were quite close to the average net sales. Having said that, you still wouldn't want to pay $323,650 for a house that really might be worth $307,625. But a spread of 5% or less in a market like we've had recently isn't bad.

But when it comes down to a specific home, you really need a Realtor to do a CMA on a property.

Hope that helps.

I think there are two factors at play here:

1) Economic - the downturn in the real estate market and home prices (comps)

2) Political -a human factor, with the County being more conservative on tax values. I know for next year DC has greatly reduced their tax values even for homes/neighborhoods where sales have been positive. It is way for the County to 'save face' in these tough times.

Thanks,

Chris

Glenda gave you a fabulous answer. She's dead on!

No, there is no correlation.

Dear MVP,

- Assesments are implied to generate revenue and are a blanket to be able to collect relative taxes.
when county cant raise assesments like in this market - they try to raise tax rates to generate revenue.

- Where as appraisal will determine the fair market value of the house and this can be highly impacted by features, functionality, desirability of the house and off course compared to last 3 to 6 months active and sold comparables to the house by adjusting and matching the siilarity to come to Fair Market Value that can be very different from Assesment.

So Assesment has usually little to do with Fair market value and is set for the Year whereas the fair market value can go up and down during the course of year!!

Hope that clarifies further.

Regrds,
Monika Kumar
703 626 3327
The RealtyGeeks Team

The Fairfax County assessments are supposed to represent 100% of fair market value as of January 1. In reality, however, the assessments are simply mass estimations based on previous sales. According to Fairfax County's web site:

"This process involves analyzing recently sold properties and adjusting the sales for differences to estimate the values of the unsold properties. DTA uses mass appraisal techniques and computer assistance to accomplish this annual task. In addition to market, there are other approaches to value such as replacement cost approach and the income approach. The professional appraisal staff within DTA researches and analyzes the available sales information each year to determine the approach to value which will yield the best assessed values as of January 1 each year, the effective date of the assessment."

Since the county doesn't actually look at each property, there's no way for them to accurately assess the true market value at a given time. The best way to know the market value is to have an agent prepare a market analysis based on sales of similar homes in the area.