Lower Merion, PA Accessory Structures: ADU Rules (2026)

Section 155-10.2.C, part of the Township's alternative-housing-for-the-elderly provisions, lets an owner convert a single-family dwelling or an existing institutional building in the LDR, MDR, IC, or IH Zoning Districts into two dwelling units, each with its own cooking facilities, essentially a restricted accessory dwelling unit. The conversion is not open-ended: everyone living in the two units must be related by blood, marriage, legal adoption, or be domestic partners, and one of the two units can hold no more than two people, one of whom must be 62 years of age or older.

The property owner must record an agreement with the Township at the Montgomery County Recorder of Deeds committing to remove the separate cooking facilities immediately once the unit stops being used as authorized, and the property must comply with Chapter 62, Building Construction, and the parking standards of Article VIII. If the restricted ADU sits inside a detached accessory structure rather than the main house, that structure has to meet the same principal-building setbacks that apply in the underlying zoning district, not a looser accessory-structure setback.

The Township also requires one of the two units to have at least twice the occupied square footage of the other, so the arrangement reads as a primary home with a genuinely secondary unit rather than a duplex. Because the use is tied to the elderly-housing purpose of § 155-10.2, the zoning permit that authorizes it is not permanent and depends on continued compliance with these conditions.