Quick answer (as of October 2026) In Williamson County, splitting land into tracts that are all 5 acres or larger, with no new road or utility construction, is exempt from the county's subdivision regulations (Section 1.04(B)(1), current version amended April 9, 2026). That follows Tennessee's definition of "subdivision" in Tenn. Code Ann. § 13-3-401(4). Being exempt from a plat doesn't make a tract buildable. Zoning lot size and density limits, 200 feet of road frontage in the RD-5 district, septic approval from the county's Department of Sewage Disposal Management, flood maps and greenbelt rollback taxes all still apply. This is general information, not legal advice.
The listing says 12 acres, "divisible." Whether you can actually put a second house on it in College Grove comes down to a handful of county rules the listing never mentions. Road frontage, soils and zoning decide it, and you want those answers before you're under contract, not after.
I've been investing in real estate since 2005 and selling it since 2013, and my mom lives in McDaniel Farms out here. Below is what the state and county rules actually say, with a link to every one. If you've got a tract in mind, DM me, text or call 615-392-1186 and I'll help you work through it.
What is the 5-acre rule in Tennessee?
Tennessee's 5-acre rule comes from the state's definition of "subdivision" for county planning, Tenn. Code Ann. § 13-3-401(4). Outside one narrow population bracket, a subdivision is the division of land into two or more lots "requiring new street or utility construction, or any division of less than five (5) acres for the purpose, whether immediate or future, of sale or building development." That's the wording the Tennessee Attorney General quoted in Opinion 07-121.
Read it the other way around and you get the rule people talk about. If every piece is 5 acres or larger and no new street or utility has to be built, the split isn't a "subdivision" under that definition, so it doesn't need a subdivision plat from the planning commission.
How does Williamson County apply the 5-acre rule?
Williamson County's subdivision regulations exempt "the division of a lot or parcel where all such lots or parcels are five (5) acres or greater in size and where no new road or utility construction ... is required." That's Section 1.04(B)(1) of the regulations adopted May 13, 2021, in the version amended April 9, 2026. Running a single service line to connect one tract to an existing utility main doesn't count as utility construction.
The same section lists what does need county review, and two items catch 5-acre splits:
- Any division that creates a lot reached by a private drive or easement without enough frontage on a public road, as the zoning ordinance defines it (Section 1.04(A)(4)).
- Any division that needs a new road or changes the right-of-way of an existing one (Section 1.04(A)(5)).
So a 20-acre tract split into four 5-acre pieces, each with its own frontage on an existing county road, may not need a plat. The same four pieces sharing one gravel drive probably do. When in doubt, ask the Williamson County Planning Department at 615-790-5725 before you sign, and talk to a real estate attorney about how the deed will describe the new tracts.
What zoning applies to land in College Grove?
College Grove is unincorporated, so Williamson County's zoning ordinance applies, and each parcel's district is on the county's Official Zoning Map. The ordinance (adopted 2012, effective January 1, 2013, with amendments listed through January 12, 2026) sets up rural districts, a College Grove Village district for the village itself, and others.
The rural district written for land east of I-65, which includes College Grove, is the Rural Development District-5 (RD-5). Here's what its table says for homes:
| RD-5 standard (residential) | Traditional subdivision | Conservation subdivision |
|---|---|---|
| Minimum lot area | 5 acres | average 3/4 acre, minimum 1/2 acre |
| Maximum gross density | 1 home per 5 acres | 1 home per 5 acres |
| Minimum lot width | 200 feet | 70 feet |
| Front setback | 100 feet | 35 feet |
| Side setback | 25 feet | 10 feet |
| Rear setback | 50 feet | 30 feet |
Don't assume a parcel is RD-5 because it looks rural. Look it up on the map, and if it's in another district, read that district's table instead.
How much road frontage does a lot need in Williamson County?
Under Section 17.02(B)(1) of the zoning ordinance, every lot has to abut a public road for at least the district's minimum lot width. In RD-5 that's 200 feet for a traditional lot. That standard applies to all development unless the ordinance says otherwise.
The exception is Section 17.03. Up to five residential lots, each 5 acres or larger, can share an access easement if they're created by a subdivision plat. The easement has to be at least 50 feet wide, each lot has to abut it for the minimum lot width, and easements have to stay at least 200 feet apart.
If a tract you like has a narrow strip to the road, measure that strip before you fall in love with the view.
Can you build a house on a 5-acre tract in College Grove?
Yes, if it clears three things the county checks separately: the zoning district and its lot size and frontage rules, approval for a septic system (or another approved wastewater option), and whether the building site is in a flood zone. Williamson County's subdivision regulations say lots served only by individual septic systems need the larger of the zoning minimum or the septic regulations' minimum lot area, and the system has to sit on the lot it serves.
Williamson County also allows a family subdivision, for gifting or selling a smaller lot to an immediate family member, in some districts. The zoning ordinance sets a 1-acre minimum lot, a 130-foot minimum width and a sliding cap: a 5 to 9.99 acre parcel can add one family lot, and a 50-acre-plus parcel can add five. Both parties sign an affidavit, and the new lot carries a restrictive covenant against transfer outside the family for 15 years, with exceptions for involuntary transfers like foreclosure or death. If that's your plan, get a real estate attorney involved before you buy.
Who approves septic systems in Williamson County?
In Williamson County, septic systems are approved by the county's Department of Sewage Disposal Management, 615-790-5751, not directly by the state. TDEC lists Williamson as one of nine "contract counties" that run their own septic programs. The county's subdivision regulations say all individual subsurface sewage disposal systems "shall be approved by the Department of Sewage Disposal Management" under the county's own on-site sewage regulations.
What that means for you as a buyer:
- Ask the seller for any existing soil map, septic permit or approved system layout for the tract.
- If there isn't one, make your offer contingent on the county's septic approval for the house size you want.
- Don't start a driveway or clear a house pad before the permit. TDEC's own guidance says a septic permit should come before any dirt work or construction, including the building pad.
TDEC's page also notes that for its own subdivision evaluations, a division into tracts that are all 5 acres or larger isn't a subdivision. In Williamson County that review runs through the county department, so call them first.
How do you check a College Grove tract for flooding?
Look up the parcel on FEMA's Flood Map Service Center before you make an offer. Williamson County's College Grove Village Special Area Plan says many properties on the east side of the village sit in the 100-year floodplain of Overall Creek, which feeds the Harpeth River, and it notes steep slopes and mature woods east of Horton Highway. A tract can be mostly dry and still have its only good house site in the floodplain, so look at where you'd actually build.
What happens to greenbelt when you buy land in Tennessee?
Tennessee's greenbelt law, the Agricultural, Forest and Open Space Land Act of 1976, lets qualifying land be taxed on its current use instead of market value. Agricultural land has to be at least 15 acres, including woodlands and wastelands, and either be a working farm unit or meet a 25-year family farming test. Forest land also needs 15 acres. Open space needs at least 3 acres and a planning designation or a qualifying easement.
Three things matter when you buy greenbelt land, per the Tennessee Comptroller's Greenbelt Handbook (revised May 2025):
- You have to reapply in your own name. A change in ownership means a new application, due by March 15 for the next tax year, or the land drops out of greenbelt.
- Rollback taxes come due if the land is disqualified. They recapture the taxes saved, and for agricultural land the state's application form says that's the last three years. Rollback taxes are a first lien on the land.
- When a sale disqualifies the land, the seller is liable for rollback taxes unless a written contract or statute says otherwise (Tenn. Code Ann. § 67-5-1008). Put it in the contract either way.
Split a 20-acre greenbelt farm into four 5-acre tracts and, on its own, each tract is under the 15-acre agricultural minimum. Ask the Williamson County Assessor of Property before you close, and get the contract language right.
Property tax figures are the county and city rates published for the year shown and are for planning only. Your actual bill depends on the assessed value, any exemptions and the city or district the home sits in. Confirm with the county assessor or trustee and your tax professional before you rely on a number.
What utilities should you check on rural College Grove land?
Check water, sewer or septic, and power at the road for the specific tract, because none of them is a given out here. Williamson County's subdivision regulations say no subdivision is approved until wastewater disposal is provided for, and that whoever provides sewer has to put its intent to serve in writing. For a single tract, that means three questions:
- Is there a public water line along your road frontage, and what does a tap cost?
- Is septic approved for the house you want, or is there a utility sewer option?
- How far is the nearest power line from your house site?
What should you do before you make an offer on land in College Grove?
- Pull the zoning district from the county's Official Zoning Map.
- Measure the road frontage on every tract you'd create.
- Look up the flood map for the house site.
- Get the septic answer from the Department of Sewage Disposal Management, or make your offer contingent on it.
- Ask the assessor whether the land is in greenbelt, and write rollback responsibility into the contract.
- Talk to a real estate attorney about the deed, any easements and whether a split needs a plat.
If you're comparing raw land with a finished lot in a builder neighborhood, my pages on Falls Grove and The Grove cover what you get when the subdivision work is already done. For the rest of the area, see my College Grove guide. Already own land out here and wondering what it's worth? Start with my home evaluation page.
Frequently asked questions
What is the 5-acre rule in Tennessee?
Under Tenn. Code Ann. § 13-3-401(4), a split into pieces of less than 5 acres for sale or building, or any split that needs a new street or utility, is a subdivision. If every piece is 5 acres or larger and nothing new has to be built, it isn't a subdivision under that definition.
Do I need planning commission approval to split land in Williamson County?
Not if every tract is 5 acres or larger and no new road or utility construction is needed, per Section 1.04(B)(1) of the county's subdivision regulations. A tract reached only by a private drive or easement without enough public road frontage still needs county review.
How much road frontage does a lot need in Williamson County?
A lot has to abut a public road for at least its zoning district's minimum lot width, which is 200 feet for a traditional lot in the RD-5 district. Up to five lots of 5 acres or more can instead share a 50-foot access easement created by plat.
Who approves septic systems in Williamson County, TN?
Williamson County's Department of Sewage Disposal Management, 615-790-5751. Williamson is one of TDEC's contract counties, so the county runs its own septic program.
Can I build a house on 5 acres in College Grove?
Yes, if the tract meets its zoning district's lot size and road frontage rules, gets septic approval from the county and has a building site outside the flood zone. Check all three before you buy.
What happens to greenbelt when land is sold in Tennessee?
The new owner has to reapply by March 15 or the land is disqualified. If a sale disqualifies the land, the seller owes the rollback taxes unless a written contract says otherwise.
Do I need a lawyer to buy land in College Grove?
For anything beyond a simple purchase of an existing tract, talk to a real estate attorney, especially if you plan to split the land, rely on an easement or buy greenbelt land. This page is general information, not legal advice.
Want help sizing up a College Grove tract?
Send me the address or the listing and I'll walk through zoning, frontage, flood maps and greenbelt with you before you make an offer. DM me, text or call 615-392-1186.
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