A house on the next street may have sold for far more than yours. That does not automatically make it useful evidence. It may be larger, in a different subdivision, a different property type, or simply too old to say much about the market reflected in your current county assessment. The 24 month comparable sales rule is a practical guardrail against that kind of selective comparison.
For Maricopa County homeowners, the rule means looking at recorded sales from the prior 24 months, then asking whether those sales are truly similar enough to provide a fair reference point. Recency matters, but it is only one part of a credible comparison. A recent sale that is not comparable can be just as misleading as an old sale that is.
What the 24 Month Comparable Sales Rule Means
The 24-month window limits a review to sales that occurred during the two years before the relevant valuation analysis. It is designed to keep the evidence connected to the market that produced the county’s assessed value, rather than relying on a sale from a substantially different market cycle.
That distinction can matter in fast-changing parts of Maricopa County. A sale from several years ago may reflect a very different level of inventory, buyer demand, borrowing costs, or new construction activity. Even if the home looks similar on paper, the price may no longer be a useful benchmark.
A 24-month cutoff does not mean every sale inside the window is automatically valid. It means the sale is recent enough to be considered. The next question is whether it is a genuine comparable.
The rule also works in the other direction. An older sale may support a homeowner’s intuition about a neighborhood, but a transparent assessment check should not stretch its time window just to find a number that supports a preferred result. We could widen the search and produce more sales. We don’t. More data is not better if the added data is stale.
Why Recent Sales Are More Useful Than a Single Big Sale
County assessments are not based on one eye-catching transaction. A sound comparison looks for a pattern across relevant sales. One unusually high or low sale can be affected by condition, timing, renovations, concessions, lot characteristics, or buyer circumstances that public records do not fully explain.
This is why a review should resist the temptation to start with the most favorable nearby sale. A homeowner who finds one low sale may reasonably ask questions, but one sale alone does not establish where a comparable home should fall in the market.
A group of recent, similar sales is more informative. It can show whether an assessment is broadly higher than the local evidence, generally in line with it, lower than it, or unsupported because there simply are not enough appropriate recorded sales to make a responsible call.
That last result is not a failure. It is an honest description of the available public data. In a small subdivision, a community with few resales, or an area dominated by newly built homes, the evidence may be too thin for a reliable comparison.
Recency Is Only One Comparable-Sale Test
A 24-month rule is useful because it prevents stale evidence from taking over the analysis. Still, time alone cannot make two properties comparable. LevyRight applies several limits together so that a result can show its work.
First, the properties need to share the same property classification. A detached single-family home should not be casually compared with a condominium, townhouse, or a property with a materially different classification. These property types can trade in different market segments, even when they are close together.
Second, living area must be within 15%. Square footage is not the whole story, but it is one of the clearest, consistently available public-record characteristics. Comparing a 1,600-square-foot home with a 2,600-square-foot home can create a false impression of value, particularly where larger homes command a different price range or have different layouts and amenities.
Third, the sales must be within the same subdivision. A map may make two homes look close, yet the boundary between subdivisions can correspond to meaningful differences in construction era, lot size, community features, school-area preferences, or buyer demand. A nearby sale is not necessarily a neighborhood comparable.
Finally, the method requires at least five comparable sales. That minimum helps prevent an assessment check from being driven by a thin sample. It is not a promise that five sales answer every question about a property. It is a baseline for avoiding a conclusion built on one or two convenient transactions.
A Simple Example of How the Rule Filters Sales
Imagine a homeowner in Peoria sees eight recorded sales near their home. At first glance, all eight might seem relevant because they are nearby. Once the filters are applied, the picture can change.
Two sales may be more than 24 months old. Another may be a townhouse when the home being reviewed is detached. Two more may be substantially larger than the 15% living-area range. One may sit across a subdivision boundary where homes routinely have different lot sizes and market positioning.
Only two sales remain. Those two may be interesting, but they do not meet the five-sale threshold. The accurate output is not a forced assessment conclusion. It is that the public records do not provide sufficient comparable-sale data under a consistent method.
Now consider a Mesa subdivision with 14 recent recorded sales. After applying the same property-classification, living-area, subdivision, and time filters, seven remain. That is a stronger evidence set because the result depends on a repeatable rule, not a handpicked collection of sales.
The difference between these examples is not which homeowner looked harder. It is whether the available data can withstand the same standards in both cases.
Why a Fixed Window Is Better Than Moving the Goalposts
When someone wants a particular answer, it is easy to adjust a search until the numbers appear to support it. Expand the map slightly. Include a larger home. Pull in an older sale. Exclude the higher transactions. Each decision can sound reasonable in isolation, but together they can turn a comparison into an argument rather than an analysis.
A fixed 24-month window creates discipline. It states in advance what counts as recent, then applies that standard whether the resulting sales point higher, lower, or nowhere at all. The same is true of the subdivision, size, classification, and minimum-sale requirements.
This approach has trade-offs. Narrow filters can leave some homeowners without enough data, especially in lower-turnover neighborhoods. Broader filters may produce more sales, but they can also introduce properties that are less alike. LevyRight favors a narrower, transparent method because a weak comparison should not be made to look stronger than it is.
Public records also have limits. They may not capture interior condition, remodeling quality, deferred maintenance, unusual transaction terms, or every feature that influenced a buyer’s decision. A recorded sale price is valuable evidence, not a complete description of a home.
Questions Homeowners Often Ask
Does a sale exactly 24 months old count?
The answer depends on the date used for the analysis and the recorded transaction information available in public records. The key principle is consistent treatment: sales outside the prior 24-month window are not pulled in merely because they produce a preferred comparison.
Why require five sales instead of using the closest three?
Three nearby sales can be a useful starting point, but they leave little room for normal variation among homes and transactions. Requiring at least five helps reveal whether there is a meaningful local pattern rather than an isolated result.
What if there are no five comparable sales in my subdivision?
That can happen, and it does not mean anything is wrong with the home or the assessment. It means the available recorded sales do not meet the stated evidence threshold. “Insufficient data” is more useful than a confident-looking number based on loose comparisons.
A county assessment deserves to be examined with the same care a homeowner would expect from any consequential property figure. Start with public records, use recent sales, keep the comparison rules visible, and let the evidence determine whether there is a clear result. When the data is thin, saying so is not evasive. That honesty is the whole point.
