How to Read LA Housing Price Trends Yourself: Four Public Data Sources and the Mistakes That Cost You
· Buying Process
Four free data sources track LA prices. Learn what each shows, what each hides, and which mistakes agents see repeatedly.
When you are new to the US real estate market, the instinct is to gather price data and make a decision. That instinct is right, but the sources themselves will mislead you if you do not know what each one is designed to measure and what each one deliberately leaves out. This article walks through the four main public databases used in Southern California, explains the mechanism behind each one, shows you what mistakes people actually make when reading them, and explains what question each source can answer, and what it cannot.
The first and most commonly misread source is the Multiple Listing Service, or MLS. The MLS is not a website; it is a database maintained by real estate boards in each area, and it contains every property that a licensed agent has listed for sale. The critical fact is the word "listed." If a home sells without being listed, sold off-market, or sold to a family member, or sold at auction, it will not appear in the MLS at all. The MLS shows you what was offered for sale and what price it eventually received, but it does not show you the universe of homes that actually sold. In Los Angeles County, the MLS is maintained by the California Regional Multiple Listing Service, or CRMLS. When someone says they checked "MLS data," they usually mean they looked at a aggregated feed from CRMLS on a consumer site like Zillow or Redfin. This is where the first mistake appears: the consumer sites lag the actual MLS by 24 to 72 hours, and they apply their own algorithms to estimate values, which do not always match what MLS brokers see. If you need precision on recent transactions, you must get the data directly from a MLS data feed subscription, not from a consumer portal.
The second source is the County Assessor's database. Every property that sold in Los Angeles County, whether or not it was listed, creates a new assessed value record. The Assessor uses this sale price to calculate property tax under California Prop 13, which applies a base rate of 1% of assessed value, with the effective rate commonly around 1.1–1.25% depending on local taxes. The Assessor's records are public, searchable by address, and updated quarterly. This is the most complete record of actual sales because it captures off-market sales, estate sales, and other transactions that never touched an agent. The trap here is that Assessor records show the sale price reported to the county, which is not always the true price paid, sometimes because of creative financing, sometimes because of family transfers, and sometimes because of simple data-entry error. Also, the Assessor's database lags by one to three months. If you are trying to understand what homes actually sold for in a specific neighborhood, the Assessor's data is more complete than the MLS, but it is also slower.
The third source is the County Recorder's deed database. When a sale closes, the signed deed is recorded at the Recorder's office. The Recorder's database is the legal record of ownership transfer and is searchable by property address, buyer name, seller name, and sale date. The Recorder shows the price, the parties, the date, and the recording date. This database is also public and typically updated within days of recording. Many people confuse the Recorder with the Assessor: the Recorder is the deed custodian (who owns what, when), while the Assessor is the tax authority (what is it worth for tax purposes). The Recorder's price is the stated price in the deed, which is legally binding but may be subject to terms (seller financing, trade of other property, or assumption of debt) that make the cash-to-cash price different. Reading the Recorder's deed alone will not tell you if the buyer paid cash, got a loan, or traded other assets.
The fourth source is the sales comparison database, typically offered as a paid subscription by vendors like CoStar LoopNet, CBRE, Zillow for professionals, or Redfin. These vendors harvest data from the MLS, the Assessor, the Recorder, and property records databases, then combine them into a single view. They fill gaps, correct errors, and offer tools to filter by property type, size, date, and location. The power of a comparison database is that it lets you see trends across time and across neighborhoods. The trap is that these databases are only as good as their inputs, and they inherit all the errors from the three sources above. If the MLS data was delayed, or the Assessor's price was recorded wrong, or the deed price did not reflect the true transaction, the comparison database will show the same error.
Now for the mistakes people make. The most common mistake is treating MLS-listed price as sold price. In the MLS, every home has a "list price" and a "sold price." New buyers often focus on the list price and assume that homes are selling near that number. This is wrong. The sold price is what matters. Comparing today's list prices to last year's sold prices is a category error, you are comparing apples to last year's oranges. The second mistake is assuming that a database is current. The MLS lags 24 to 72 hours; the Assessor lags one to three months; the Recorder is usually current within a few days but depends on the county's scanning and uploading schedule. If you are looking at data more than 10 days old, you are looking at historical data, not market conditions. The third mistake is confusing "sale price" across different databases. The MLS sold price may differ from the Assessor's assessed value, which may differ from the Recorder's deed price, because each one is measuring something different, at a different time, under different rules.
Here is a worked example of how this plays out in practice. Suppose you are looking at a single-family home listed in Los Angeles at $1,200,000 on April 15, 2026. You check Zillow and see the listing. Two weeks later, the property is marked "sold" in Zillow at $1,150,000. You note that down. But you want to confirm, so you check the Recorder's website directly. The deed has not yet been recorded, it usually takes 7 to 14 days after closing for the deed to appear in Recorder records. You wait another week, and the deed shows up with a price of $1,150,000, confirmed. Now you go to the Assessor's website, but the property still shows the old assessed value from the previous owner's purchase, because the Assessor has not yet updated the 2026 sale into the system. The Assessor's update will come through in the next quarterly cycle, roughly 60 to 90 days after the sale closed. In the meantime, you now have three data points: the MLS sold price ($1,150,000), the Recorder's price ($1,150,000, now confirmed), and no Assessor update yet. All three are consistent, but that consistency only arrived because you checked multiple sources and waited for the lag times. If you had stopped at Zillow on day 16, you would have had the right number but no confirmation.
The way to use these sources correctly is to ask a specific question and then choose the right source. If your question is "what has the MLS recorded as sold in my neighborhood in the last 30 days?" use the MLS via CRMLS or a professional feed, and accept that you are seeing only listed properties. If your question is "what is the most complete record of actual sales in my neighborhood, including off-market sales?" use the Assessor's database, and accept a one- to three-month lag. If your question is "has a specific property closed, and what does the deed say the price was?" use the Recorder, and accept that the stated price may not be the full economic consideration. If your question is "what is a realistic price for a property of this size, type, and condition in this neighborhood, accounting for recent comparable sales?" use a professional sales comparison tool, and understand that it inherits the limitations of all three underlying sources.
One final mistake: assuming that trend direction is the same as magnitude. When you read that prices have moved up or down, that does not tell you by how much, in which submarkets, or for which property types. A database showing that prices moved up does not tell you if they moved up $10,000 or $100,000, or if they moved up in one part of the county while staying flat in another. To understand magnitude, you must do the work of sampling multiple comparable properties over time, which is why this is the work an agent does, not a task for a data portal. The data sources are tools for confirmation and for spotting direction; they are not a substitute for professional analysis of comparables.
The reason to understand these sources is not to become a data analyst, but to know what you are looking at when you talk to a real estate professional. When a real agent pulls data, they are combining information from multiple sources, accounting for lag times, and filtering for true comparables. They know which database to trust for which question. They know when the lag times mean a database is not yet reliable. They can read a deed and understand what the price actually represents. This is specific knowledge that takes years to build.
If you are serious about understanding the LA market before you buy or sell, start by identifying which question you actually need to answer. Then pick the right source. Then wait for it to update. Then cross-check against at least one other source. The impulse to act fast is natural, but the data will still be there in a week, and it will be better.