What records explain additional residential units at a Kingston home?

The urban residential zone tables in Zoning By-law 2022-62 allow a house, semi-detached house or townhouse a maximum of 4 dwelling units per lot, including accessory houses. In the area shown as the Fourth Residential Unit Holding Area on Schedule D3, a holding overlay applies to the fourth unit: it can't get a building permit until the City is satisfied that water, wastewater, natural gas and electrical capacity are adequate and any studies it asks for are done. Schedules D1 and D2 hold back added units in constraint areas and in the rural area.

The City's page says additional units are possible on most properties in Kingston, except rural properties, and are not permitted in a cellar or basement in the lands marked Sewer Surcharging, on lands marked Sewer Capacity Limitations or Loughborough Lake, on a lot that already holds two or more dwelling units, a garden suite, a boarding house or a lodging house, or on lands subject to natural hazards. It says owners must legalise existing units, which can mean renovations to meet the zoning and the Building Code, so a permission in the zone does not make an existing unit lawful.

• Additional residential units (ARUs): the City's page: where units are allowed and where they are not
• Zoning By-law 2022-62, Part 1: the urban residential zones and the Schedule D3 holding overlay, clause 5.4.5 (PDF)

Extra units allowed is in the free check as a summary of the City's rule, from our hand-kept table of city rules, and the full report reads the lot's zone where the City's zoning map is open data we can use; where it isn't, the report's line says where the City publishes it. Neither is confirmation that a particular unit holds a permit or may be occupied.

Free check: pick “Extra units allowed” See the sample report