Gemini said
Since you want to focus specifically on the main building and its basement while excluding the separate Olive Avenue lot, we need to adjust the square footage and lot size to reflect only the primary parcel.

Tax records often underreport functional space because they focus on "above-grade" area. For your MLS listing, you want to highlight the usable space to show the true value.

Corrected Data for Primary Parcel (247 S Riverside)
Category Data for MLS Notes
Total Building SF 21,200 SF Combines 10,200 SF main floor + 11,000 SF basement.
Lot Size (Acres) .2433 AC This matches the specific parcel footprint from your tax info.
Lot Sq Ft 10,600 SF The land area of the primary parcel only.
Stories 1 + Basement Use this to explain the discrepancy between tax records and actual SF.
Updated MLS Public Remarks (Basement Focus)
Note: This version emphasizes the massive storage/production capacity of the basement without mentioning the extra parking lot.

Turn-Key Business & Real Estate Opportunity in Downtown Rialto

A rare chance to acquire J&J Auto Fabrics, a premier upholstery business established in 1982, along with its substantial real estate. This offering features a versatile 10,200 SF main floor complemented by a massive, fully functional 11,000 SF basement, totaling over 21,000 SF of usable space. The basement is a standout feature, equipped with a grade-level roll-up door for easy loading and inventory management.

Ideally located directly across from the Rialto Metrolink Station, the property benefits from high visibility and DMUZ (Downtown Mixed-Use) zoning, providing excellent long-term investment potential. Sale includes the business name, goodwill, and all existing inventory. Whether you are looking to continue the legacy of a 40-year upholstery staple or repurpose the massive square footage for a new creative or industrial use, this property offers unmatched scale in the heart of the city.