Westminster · Building on your lot

Lot splits under SB 9 in Westminster

Westminster's own rules on lot splits under SB 9, with the code text for every value.

Ask about lot splits under SB 9 in Westminster See coverage

Each rule below links to the section of the Westminster Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What Westminster's code says

Westminster code What Westminster's code adds
How the lot may be divided	Neither new lot can be smaller than 40% of the original lot's area. Applies: An urban lot split into no more than 2 lots of about equal area. § 16.12.020 · code text The parcel map divides an existing parcel to create no more than two new parcels of approximately equal lot area, provided that one parcel shall not be smaller than 40% of the lot area of the original parcel.
Minimum new lot size	Each new lot must be at least 1,200 square feet. Applies: Both new lots. § 16.12.020 · code text Both newly created parcels shall not be smaller than 1,200 square feet in area.
Setbacks	Side and rear setbacks are 4 feet. Applies: Except an existing structure, or one rebuilt in the same place and to the same size. § 16.12.040 · code text Except for those circumstances described in Subsection C above, the setback for side and rear lot lines shall be four feet. No setback is required. Applies: An existing structure, or one built in the same place and to the same size as an existing structure. § 16.12.040 · code text No setback shall be required for an existing structure or a structure constructed in the same location and to the same dimensions as an existing structure.
Standards	Only lots in the single-family R1 zone qualify. § 16.12.020 · code text The parcel is located within a single-family residential R1 zone. No more than 2 new lots. Applies: Urban lot splits. § 16.12.020 · code text The parcel map divides an existing parcel to create no more than two new parcels of approximately equal lot area, provided that one parcel shall not be smaller than 40% of the lot area of the original parcel. No more than 2 units on a lot. Applies: Each lot created by the split. § 16.12.020 · code text The lot split does not create more than two units on a parcel. Shared driveways must be at least 20 feet wide. § 16.12.040 · code text Shared driveways shall have a minimum width of 20 feet. Each new lot needs direct access to the public right-of-way. Applies: By direct lot frontage or an access easement. § 16.12.040 · code text Each resulting lot shall have direct access to the public right-of-way. This may be by way of direct lot frontage or through an access easement.
Parking	1 parking space per unit. § 16.12.040 · code text Parking shall be required at the rate of one space per unit.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

Can I split my lot under SB 9 in Westminster?

Westminster's code: Each new lot must be at least 1,200 square feet. (Both new lots.) (§ 16.12.020); Only lots in the single-family R1 zone qualify. (§ 16.12.020).

General information, not legal advice.

Ask about a specific Westminster property

Ask GoCodebook how Westminster's lot splits under SB 9 rules apply to your situation and get an answer that cites the section.

Ask your question

More on building on your lot in Westminster

All building on your lot rules in Westminster

Fences and walls in Westminster

Sheds, garages and other accessory structures in Westminster

Swimming pools in Westminster

Park and impact fees for new homes in Westminster

Noise and construction hours in Westminster

Garage and yard sales in Westminster

Parking spaces required for homes in Westminster

Home alarm permits and false alarms in Westminster

Westminster Municipal Code — full text