Granny flats in Moreton Bay: rules, costs and builders

Big Small Haus is a licensed Queensland builder, QBCC 15506005, and the authorised installer for Outhaus. Moreton Bay is home turf: Outhaus builds its homes in the yard at Laceys Creek, out past Dayboro, which is inside Moreton Bay. We install and build across the city, from Redcliffe and the peninsula to North Lakes, Petrie, Strathpine and Albany Creek, and out to Samford Valley, Dayboro and the acreage behind them.

Moreton Bay is the council that catches people out. Before size or design, it has a minimum lot size and frontage, and below it the answer is no.

Rule	What it says
Minimum lot and frontage	600 m² and 12.5 m frontage in the Suburban neighbourhood and Coastal communities precincts; 450 m² and 10 m everywhere else. Both must be met
Maximum size	45 m² GFA on lots 450 to 800 m²; 55 m² over 800 m²; 100 m² in Rural and Rural residential zones
Distance from the house	Within 10 m (50 m in Rural and Rural residential)
Look from the street	Must read as one dwelling from the street; must face the house in some precincts
Parking	One extra space, next to the house's parking
Approval	Accepted development if it meets the rules, so building and plumbing approval only

The one to check firstIf your lot is under 450 m², or under 600 m² in the Suburban neighbourhood or Coastal communities precinct, or your frontage is too narrow, a granny flat fails the code. The fallback rule repeats the same numbers, so there's no argument to win. Treat it as a no. On some lots near a train station or centre, a dual occupancy can be an option instead.

A module for a Moreton Bay job, clad and glazed in the factory before delivery

If you miss a rule

It doesn't stop the project automatically: council becomes a referral agency on the building application and assesses it. But for lot size and frontage the numbers are fixed.

Not sure about your block?Send us the address. We check the zone, lot size, overlays, sewer and crane access, and tell you straight.Get a quote

Infrastructure charges

Moreton Bay's current charges resolution doesn't mention secondary dwellings. The older resolution exempted them. Confirm with council before you budget.

Coming

Council has started work on a new planning scheme. No draft or date yet, so the 2016 scheme still applies.

Rules that apply across Queensland

You can rent a granny flat to anyone, not only family. The state removed the family-only test in September 2022. It still has to be secondary to the main house and can't be sold separately.
You always need a building approval from a licensed certifier, and a plumbing approval from council.
Queensland's new Housing Code started on 1 September 2026 with new setbacks. Each council keeps its current rules until it adopts the new code, by 1 September 2029 at the latest.

What we'd check on your block

The zone and the size cap, lot size and frontage, every overlay, where the sewer runs, the slope, and whether a truck and crane can get in. Send us the address and we'll tell you straight.

Getting a granny flat in on a Moreton Bay block

Water and sewer: Unitywater

Moreton Bay's water and sewer belong to Unitywater, and it is clear about granny flats: if the secondary dwelling isn't on a separate lot, a separate water or sewer connection can't be provided, and it's serviced through private plumbing on the property. Council says the same thing from its side. The house and the granny flat share a single water connection and meter, electricity connection and meter, wastewater connection, and street number and letterbox. The shared meter is the master meter, and any sub-meter follows Unitywater's sub-metering policy.

Before building near pipes, Unitywater suggests ordering a Detailed Infrastructure Plan for the lot. If there are assets on your block or the neighbour's, a certifier assesses the work against the Queensland Development Code MP1.4, and if it can't comply you apply to Unitywater to build over or near them, with a site plan, elevations and the engineer's Form 15. Building into a Unitywater easement is a different story: Unitywater says those requests are rarely granted.

Lot size, flood and the coast

Start with the minimum lot size and frontage above, because below it the answer is no. Then flood. Council's info sheet sets the minimum habitable floor height at 300 mm above the defined flood event level east of the Bruce Highway, 500 mm east of the highway inside the erosion prone area, and 750 mm for every site west of it. In the high and medium risk flood areas, a new secondary dwelling needs approval. Council's flood check development report gives the levels for your lot. On the peninsula and Bribie, the coastal hazard overlay comes into it too.

Crane access in Moreton Bay

The module's trip is short: Laceys Creek to most of Moreton Bay is a morning's drive, not an interstate haul. The last few hundred metres are the hard part. Older Redcliffe and Margate streets are narrow with power along the verge, the newer estates have small lots with fences close together, and the hills around Dayboro and Samford mean slopes, long driveways and the odd tight bend. We walk all of it before we book the crane.

What an install costs in Moreton Bay

Most installs run $70,000 to $140,000 inc GST, on top of the price of the home. In Moreton Bay the short haul from Laceys Creek helps on delivery. What pushes it up: a flood level that lifts the floor by up to 750 mm west of the highway, a Unitywater main in the way, a sloping hinterland block that needs retaining or taller piers, and a crane that has to reach over the house. A flat suburban lot with room for the crane lands at the lower end.

Our Moreton Bay jobs

Outhaus homes are built in the shed at Laceys Creek, steel frame first, then cladding, fit-out and paint, before they go out on the truck. Right now we're installing an Outhaus modular home at Petrie, a job under way through October and November 2026: footings, crane day, connections and sign-off.

Modules being finished in the shed at Laceys Creek, in Moreton Bay

Questions about granny flats in Moreton Bay

Does Moreton Bay charge infrastructure charges on a granny flat?

Council's current charges resolution doesn't mention secondary dwellings. The older resolution exempted them. Confirm with council before you budget.

My lot is 520 m² in the Suburban neighbourhood precinct. Can I build one?

No. That precinct needs 600 m² and 12.5 m of frontage, both. Below that a granny flat fails the code and the fallback rule repeats the same numbers. A dual occupancy may be an option on some lots near a station or centre.

Can the granny flat have its own water meter?

Not its own connection. Unitywater says a secondary dwelling on the same lot can't get a separate water or sewer connection, and council's code has both dwellings share one water connection and meter. A sub-meter behind the master meter follows Unitywater's sub-metering policy.

How high does the floor need to be on a flood-mapped block?

At least 300 mm above the defined flood event level east of the Bruce Highway, 500 mm east of it inside the erosion prone area, and 750 mm west of it.

Can I rent it out?

Yes, to anyone. The state removed the family-only test in September 2022. It still has to stay secondary to the house and can't be sold separately.