How many bedrooms is my Davidson County septic approved for?

Where to get the number

Metro Public Health’s Septic and Sewage Disposal Systems division holds it. Their published services include a “How Many Bedrooms?” request, which returns the approval date, inspection dates, and the number of bedrooms an existing residence is approved for.

You will need the property’s map and parcel number or tax ID. If you do not have it, Metro’s online property information will give it to you.

Environmental Engineering Services: 615-340-5604.

That division also handles soils interpretation, system design, percolation-test monitoring and groundwater protection for the county, which is why the records sit with them.

Why the number matters

It is not a bureaucratic detail. Four things follow from it.

1. It is the system’s design capacity

Septic systems are sized by bedroom count, which is used as a proxy for daily wastewater flow. A three-bedroom approval means the tank capacity and drain field area were calculated for the flow a three-bedroom household is assumed to produce. Exceed it consistently and you are running the system above design — which shortens the field’s life regardless of how diligently you pump.

2. Advertising above it is unlawful

In Tennessee it is illegal to advertise a home for more bedrooms than its septic is approved for, and the person advertising it is liable for misrepresentation. This bites hardest at sale, and it is one of the more common problems found during real-estate septic inspections.

3. It affects short-term letting

Nashville has a very large short-term rental market, and a listing that sleeps ten in a house approved for three bedrooms is loading the system at several times its design flow on a peak weekend. The advertising rule is written about advertising, and a short-term rental listing is advertising. Worth knowing your number before you list.

4. It should inform your pumping interval

If the household exceeds what the system was permitted for, the standard three-to-five-year interval does not apply to you. The right interval is capacity against actual flow, measured.

Before you extend

If you are adding a bedroom, converting an attic or finishing a basement with sleeping space, check the approval first. Adding capacity to a house without adding capacity to the system is how a working field gets destroyed in a few years, and increasing the approved count requires permitting, a site evaluation including a soil morphology assessment by a soil scientist, and sufficient suitable area on the parcel.

While you are checking, ask about the reserve area too. Tennessee requires the system to sit entirely within its own parcel with setbacks, and requires the parcel to retain enough room to replace the system should it fail.

What to do with the answer

Situation	What it means
Bedrooms match the approval	Standard intervals apply; keep the record for a future sale
House has more bedrooms than approved	Get advice before listing or letting; shorten your pumping interval now
Planning to add a bedroom	Check whether the system can be upgraded before committing
Letting short-term	Compare the approval against your listing’s sleeping capacity

Bottom line

Call Metro on 615-340-5604 with your map and parcel number and get the figure. It takes one phone call and it affects what you can advertise, what you can build and how often you should pump. Then call (615) 234-9048 if you need the system assessed against it.