Three tenants is not the whole answer
Three unrelated people sharing a kitchen or bathroom can form a smaller HMO. A family living together is a different household arrangement. This question needs local licensing rules as well as occupancy details.
Check for an additional licensing designation
Lambeth, Reading and Sandwell provide examples of borough-wide additional schemes for smaller HMOs. Their designation dates and scope differ. The checker identifies likely requirements for ordinary houses using the reviewed records.
Ask the council about exceptions
Resident landlords, flats, converted buildings, statutory exemptions and unusual occupation need individual review. A missing scheme record is not proof that no licence is required.
Check your property
Use the free checker with your council and property facts. Partial boundaries, flats, converted buildings, resident landlords and statutory exemptions still need individual review.