Brentwood's New Lot Rules Fall Hardest on the Lots People Rebuild

"Upon the recording of this Declaration in the office of the Register of Deeds for Williamson County, Tennessee, the foregoing restrictions and covenants shall run with the land and shall be binding on Declarant and all subsequent owners of the Property."

That sentence comes near the end of the City of Brentwood's standard Declaration of Restrictions and Covenants. The form goes with the stormwater controls the city has required on qualifying residential projects since August 1, 2026. The new rules make a home's buildable room depend on when its lot was platted, and they show up in the paperwork of the homes most likely to change hands after a rebuild. Buyers looking at older homes on large lots and owners selling those lots should know how this summer's rules work before anyone writes an offer.

What the next owner inherits

The covenant is part of the Residential Infill Development Permit, or RIDP, created by Ordinance 2026-06. When a project needs green infrastructure controls such as cisterns, dry wells, modified French drains, permeable pavers, rain gardens or vegetated filter strips, the owner signs a declaration and a long-term maintenance plan. According to the city's form, the declaration commits the owner to the following:

1. Maintaining the controls under the accepted plan, including scheduled preventive maintenance, grass cutting and trash removal.
2. Inspecting the systems every year and keeping records of inspections and repairs, which must be produced if the city asks for them.
3. Granting the City of Brentwood and its contractors a perpetual right of entry at reasonable times to inspect or operate the systems.
4. Following city orders to perform maintenance within a deadline set by the Engineering Department. The form states the city has no duty to maintain or repair the systems itself.
5. Reimbursing the city for any judgment against it that results from the owner's failure to meet these obligations.

Another clause affects anyone with plans for the yard. Before any change, addition or relocation of the improvements, the owner or "successors and/or assigns" must show the Engineering Director that the change will not interfere with how the controls work. Any approved change gets recorded on a map that references the original instrument. The covenant can only be modified by a recorded instrument signed by the owner and the city. It becomes void if the structures are demolished and the property is prepared for redevelopment.

Someone buying a Brentwood home rebuilt or expanded after August 2026 may therefore get an annual inspection schedule and a rain garden that can't simply be regraded into a play lawn.

Why the older lots carry the weight

Whether a project needs an RIDP depends on two tests. First, it has to create a net increase of 800 square feet or more of impervious area. Second, it has to meet one of these conditions: new residential development, a substantial rebuild lot, a location in the Hillside Protection Overlay District, or a Transitional Lot. Brentwood's code defines "transitional" property as lots with at least a 15 percent grade but less than 25 percent. The city's stormwater design manual then sorts projects by how much hard surface they add. As written, the first two ranges both include 8,500 square feet, so a project at exactly that figure is a question for Brentwood Engineering:

• Tier 1, 800 to 8,500 square feet: treat the first inch of rainfall runoff from the added area using green infrastructure.
• Tier 2, 8,500 to 20,000 square feet: the same treatment, plus peak-flow calculations showing no increase in the 10-year, 24-hour storm peak leaving the site.
• Tier 3, more than 20,000 square feet: full engineering review, which may require a stormwater management plan.

The Engineering Director can move any project into a higher tier because of site constraints. At the board's early June discussion, staff said most projects would fall in the lowest tier, according to a Citizen Portal meeting summary.

The exemption is the part that sorts lots by age. The manual says:

A RIDP may not be required for new residential development, substantial rebuilds, or rehabilitation projects for lots platted after June 1, 2008 that that are connected to, or are included in a development with, an approved stormwater management facility. Any exemption must be approved by the engineering department.

Newer subdivisions already drain into approved stormwater facilities, so those lots may qualify for relief. Lots platted before mid-2008 don't have that route. Those are the same lots where the trend City Manager Jason Gage described is happening. "There is a significant trend that when new homes are being built on existing lots where old houses were, the new houses are larger," he said, as reported by the Williamson Herald. "The point is to allow water to soak into the lot and let the soil do its thing." On two homes with the same acreage, a planned addition can need a permit, a recorded covenant and engineered controls on one and none of that on the other, depending on the plat date.

What an acre can hold now

The permit adds paperwork. Ordinance 2026-05 limits how much of the lot can be built on at all. Since July 30, 2026, every lot in the AR, R-1 and R-2 districts has to keep at least 40 percent as green space. That area must be "free of permanently constructed improvements such as dwellings and other buildings, driveways and sidewalks, patios and decks, swimming pools, tennis courts, and other impervious surfaces." Staff told the Planning Commission the 40 percent figure is identical to what the city already required in its OSRD district, according to a Citizen Portal summary of the July 6 meeting.

The 25 percent cap on building coverage still applies. Here is how the two limits work together on a minimum-size R-2 lot of one acre, which the city defines as 43,560 square feet:

A rebuild that pushes the house footprint toward the 25 percent cap leaves a fixed amount of hardscape for everything else, and the driveway counts against it. The R-2 setbacks also still apply: 75 feet in front, 30 feet in the rear and 20 feet on interior sides. The Williamson Herald summarized it this way: the rule "would prohibit the construction of certain structures like outbuildings, patios and sports courts if they violate the 40% rule."

Homes that already exceed the limit fall under Brentwood's general nonconforming-structure provision in the city code. A lawful structure that predates an amendment "may be continued so long as it remains otherwise lawful," and "No such structure may be enlarged or altered in a way which increases its nonconformity." We did not find language in Ordinance 2026-05 that specifically addresses lots already over the line, so the city is the authority on how a particular property is treated.

Where it surfaces in a Brentwood sale

Brentwood's one-home-per-acre density standard keeps new supply limited. The city lists Brenthaven, Meadowlake, River Oaks and Indian Point as examples of R-2 subdivisions on one-acre minimum lots. Under its Open Space Residential Development option, smaller lots are allowed only when the land saved is kept as open space, as in McGavock Farms and Taramore. The city's FY 2027 operating budget counted 121 new single-family starts in calendar year 2025, more than 9 percent above 2024. It credits the increase partly to new subdivisions and partly to redevelopment, after a 2022 low of 83 starts. The new projects on record are small. Tester Construction Group broke ground September 30 on The Five at Valley View, five homes at 5655 Valley View Road. The proposed Crews subdivision west of Hillsboro Road would add 25 lots. Commissioners approved its first reading in July, and the Herald's report listed the final reading as scheduled rather than decided.

With so little new land coming, much of the change in Brentwood homes happens on existing lots, which brings these rules into play at three points in a deal.

The buyer with plans. If the purchase depends on adding a pool, a garage or a larger footprint, two numbers matter: how much green space the lot has left and when the lot was platted. An older lot may carry permit and engineering steps that a lot platted after 2008 can avoid.

The seller of an older lot. Buyers who plan to rebuild will likely factor these steps into their offers. Being able to describe the lot's current hard-surface coverage and plat history gives a valuation something concrete to work from. Our Brentwood luxury selling guide covers how that kind of preparation fits into a listing plan.

The buyer of a recent rebuild. Any declaration is recorded with the Williamson County Register of Deeds, so it becomes part of the property's recorded history and travels with the deed. The maintenance plan and inspection records described in the form are documents a buyer can request during the transaction.

Questions we expect from Brentwood owners

What does the permit cost?

When the commission approved the ordinances on first reading, a Citizen Portal summary reported a $150 permit fee. The fee is minor next to the cost of designing and installing the controls themselves.

Does a pool alone trigger the infill permit?

The city's guidance covers new homes and additions or redevelopment that meet the criteria. It doesn't specifically say whether a pool, patio or driveway on an existing home triggers an RIDP. The 40 percent green-space rule does count pools and patios as impervious. Brentwood Engineering answers project-specific questions at 615-371-0060.

Was this a close vote?

No. The Williamson Herald reported that Mayor Nelson Andrews and Commissioners Kim Gawrys, Janet Donahue, Stevan Pippin, Anne Dunn and Ken Travis approved the measures on June 8. Andrews said "it's more about looking down the road before this becomes a problem." Ordinance 2026-05 then passed second reading on July 27.

If you own an older Brentwood home on a large lot, its value now depends partly on how much the lot can still hold. The appraisal-informed team at Moving Nashville Homes will factor green space, plat history and these new rules into a pricing conversation. Request a free home valuation and we'll go through the numbers for your lot.

This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.