There's an old saying, "What goes up, must come down." But does that apply to property taxes?

Perhaps.

Proposition 13, passed by California voters in June 1978, continues to guide assessments to this day.

It created a system for assessing property by establishing a base year value—the year a property is built or changes ownership.

Once the base year value is established, inflationary increases are limited to no more than 2 percent per year. At first there was no provision in Prop. 13 for assessed values to decline, which would allow the lowering of taxes.

In November 1978, however, voters approved Proposition 8 (not the recent Prop. 8 regarding marriage) permitting county assessors to review properties and see if the market value as of Jan. 1 in a given year had declined below the value established by Prop. 13.

The job of the assessor, an independently elected official, is to ensure fair treatment for all taxpayers.

As market conditions decline, the assessor's certified appraisers review sales of comparable properties.

This year, if the market value of a property as of Jan. 1, 2009, has declined below its Prop. 13 value, a new market value is placed on the tax roll. That lower value will be reviewed again next year and reduced further if necessary.

Property owners who believe their home may have suffered a decline in value below the last assessment (as shown on your current 2008-09 tax bill) are encouraged to wait and see what the new assessment shows on this year's bill in July.

Many property owners have been receiving deceptive solicitations by mail requiring a fee for reassessment. Do not be misled by these official-looking offers for tax relief.

This work is already underway by the assessor's staff, and it's free. It's best to wait for the assessor's new value notice in your July mail before taking independent action.

There is a ray of hope in all this.

While many economic factors—especially the cyclical nature of the real estate market—can impact the value of property, Simi Valley is still a much sought-after place to live.

Because of our area's diversified economy, strong environmental protections and unique quality of life, the declines in value here are usually not as persistent or severe as those in Southern California's inland counties.

But time will tell.