The Individual Parcel Evaluation System (IPES) is how the Tahoe Regional Planning Agency rates vacant residential lots. TRPA’s code applies it to “any single-family dwelling on a parcel that was vacant on or after July 1987.” If you are buying, selling, or designing for an empty lot at Tahoe, the IPES score is the first number to find.
What the score measures
According to TRPA’s Vacant Lots guide, vacant residential parcels were scored in 1987 and 1988 on a scale from 0 to 1,017, and “the lower the score the more sensitive the parcel.” The evaluation weighs things like erosion hazard, runoff potential, and access. Parcels that contain no area outside a stream environment zone or its setback score zero.
The IPES line
Originally, only parcels scoring 726 or higher were considered buildable. TRPA’s April 2026 IPES application lists the current lines: 1 or higher in the City of South Lake Tahoe, El Dorado County, Douglas County, and Washoe County, and 691 or higher in Placer County. A score of 725 or below is still treated as “sensitive” for coverage transfers and land bank pricing, so the old line still affects cost.
What the score means for coverage
The score comes with a base allowable coverage percentage. TRPA sets it by formula from the score; no parcel gets more than 30 percent or less than 1 percent. TRPA does not publish a simple score-to-percentage table, so use the percentage issued with your parcel’s score rather than guessing from the number. Two details trip people up:
- Bigger lots: IPES scores only a one-third-acre building site. On parcels over 14,520 square feet, the rest of the lot may need TRPA’s determination of allowable coverage.
- Buying more: coverage above the base allowance can usually be transferred in or bought from a land bank, up to a cap based on parcel size. On the California Tahoe Conservancy’s December 1, 2025 price list, South Shore potential coverage for IPES 726+ or Bailey 4–7 parcels is $7.50 per square foot, and $25.00 for more sensitive receiving parcels.
A parcel with an IPES score does not need a TRPA site assessment; see when you need a site assessment.
How to look it up on Parcel Tracker
- Open TRPA’s Parcel Tracker (parcels.laketahoeinfo.org).
- Search by address or APN. Parcel detail pages use the dashed APN, for example
/Parcel/Detail/033-693-008. - On the Parcel Details page, look under Land Capability. TRPA’s Vacant Lots guide says the IPES score is listed there.
- While you are there, check the permit and verification history on the parcel record.
- If the property is vacant and no IPES score appears, TRPA says to contact the agency, at 775-589-5333.
What it means for a vacant lot
A score at or above the line means the lot is eligible to build. It does not mean the lot is a good building site. The house, driveway, decks, and walks all have to fit inside the coverage allowance, the setbacks, and around the slope, trees, and rock. TRPA’s IPES application also requires a topographic survey of the property prepared by a licensed engineer or land surveyor. That is why buyers survey during escrow: the same survey answers whether the lot works and becomes the base map for design.
See our Tahoe lot buildability survey, or run the numbers in the TRPA coverage calculator.