Exceptional investment & development opportunity on nearly 0.5-acre flat lot! Potential for a 4-lot subdivision Survey Completed, preliminary plans available to retain the existing home and build 3 additional detached townhomes (Like an SFH). Charming split-level home offering 4 beds & 2 baths. Main level features living/dining, kitchen & breakfast nook overlooking the spacious backyard. Upstairs has 3 bedrooms & 1 bath. Lower level includes separate entrance, den, full bath, laundry, storage & flexible space for office/wine cellar/4th bedroom great for multi-gen living or rental income. Endless possibilities: add an ADU, build a pool, park RV/boat, expand or develop. Backyard includes mature fruit trees avocado, grapefruit, Santa Rosa plum, Meyer lemon, orange & bay leaf. Prime location in Castro Valley close to downtown, shops, restaurants & BART. Rare opportunity with strong upside!