Rules & Regulations of the State of Tennessee
Title 0400 - Environment and Conservation
Subtitle 0400-48 - Water Resources (Groundwater Protection)
Chapter 0400-48-01 - Regulations To Govern Subsurface Sewage Disposal Systems (Transferred from 1200-01-06)
Section 0400-48-01-.03 - SUBDIVISIONS

Universal Citation: TN Comp Rules and Regs 0400-48-01-.03

Current through September 24, 2024

(1) Approval by Other Agencies - No proposed subdivision shall be approved by the State Planning Office, a local or regional planning commission or other agency authorized to approve subdivisions until the plans for such subdivisions have been approved by the Commissioner.

(2) Lot Size - Lots shall be large enough to construct the original subsurface sewage disposal system and to provide an area for duplication of that system. The area(s) for both original and duplicate systems shall meet the provisions of these rules and be of sufficient size to accommodate a conventional subsurface sewage disposal system with thirty-six (36) inch wide trenches except where alternative subsurface sewage disposal systems are utilized.

(3) Evaluation and Lot Design - Either a High-Intensity or a General Soil Evaluation shall be conducted as described below:

(a) Soils Evaluation
1. Mapping Procedures
(i) A high-intensity soil evaluation shall be made of the entire subdivision, the entire lot or a minimum of twenty thousand (20,000) square feet (contiguous to usable soil area, if any) per lot. Each soil delineation shall be drawn and plotted using a scale of one (1) inch to one hundred (100) feet. The soil mapping shall be done by a soil consultant approved by the Department pursuant to the requirements of Rule 0400-48-01-.18. Two (2) copies of such map shall be submitted to the Commissioner.

(ii) A general soil evaluation map shall be made of the entire subdivision using a standard mapping legend provided by the Department and each soil delineation shall be drawn and plotted using a scale of one (1) inch to one hundred (100) feet. The soil mapping shall be done by a soil consultant approved by the Department pursuant to the requirements of Rule0400-48-01-.18. Two (2) copies of such map shall be submitted to the Commissioner. Soil delineations based on slopes, soil depth to rock and water problems shall be identified on the map. Each delineation appearing on the plat through soil evaluation shall be interpreted by the soil consultants in terms of eligibility for percolation tests.

2. When the services of a soil consultant are provided by the Department, three (3) copies of a plat of the site drawn to a scale of one (1) inch equals one hundred (100) feet shall be submitted to the Commissioner. The site shall be either grid staked or lots staked as follows:
(i) A one hundred (100) feet master-grid system with surveyed control stakes numbered at not more than five hundred (500) feet intervals and the location of the same on the plat. The ratio of precision of the unadjusted survey shall be a minimum of 1:1000. The plat shall show the seal and signature of the surveyor and show a bar scale. Intermediate grid stakes with numbers at not more than one hundred (100) feet intervals shall be numbered and shown on the plat. The intermediate stakes may be set by rough chaining or other methods to a lesser degree of accuracy, however, said intermediate stakes shall be within two (2) feet of the distance shown. The Commissioner may require the removal of vegetative growth such as weeds, vines and briars to permit access to all parts of the property. In wooded areas cut/flagged lines shall be maintained until the property is evaluated.

(ii) Staked lots must have a numbered surveyed stake at each corner. The ratio of precision of the unadjusted survey shall be a minimum of 1:1000. The plat shall show the seal and signature of the surveyor and show a bar scale. Intermediate ground control stakes shall be numbered and set in areas where lot corners are not visible from any point on the lot. The intermediate stakes must be set no more than two hundred (200) feet apart, and said intermediate stakes may be set by rough chaining or other methods to a lesser degree of accuracy, however, said stakes shall be within two (2) feet of the distance shown on the plat. The Commissioner may require the removal of vegetative growth such as weeds, vines, and briars to permit access to all parts of the property. In wooded areas cut/flagged lines shall be maintained until property is mapped.

3. When the service of a private soil consultant is utilized, then the requirements in subparts 2(i) or (ii) of this subparagraph shall apply.

(b) Percolation Test
1. Under authority of T.C.A. § 68-221-403(c), after a general or high intensity soil evaluation has been conducted by an approved soil consultant and the soils are found to have the following characteristics, then a percolation test may be conducted pursuant to Rule0400-48-01-.05.
(i) There shall be a minimum depth of twenty-four (24) inches of undisturbed soil.

(ii) Slopes of more than thirty (30) percent do not qualify for percolation tests unless provisions of subparagraph (4)(d) of Rule0400-48-01-.04 are met.

(iii) No water problem shall exist. A water problem shall be considered to exist if any of the conditions are present as listed in the "Soils Handbook of Tennessee."

2. Where a percolation test is required to determine the percolation rate for a conventional system, the percolation holes used to determine this rate must be located at the intersection of lines in a grid pattern with maximum perpendicular distances of fifty (50) feet between the lines of the grid. Each hole shall be considered reasonably representative of a square area of two thousand five hundred (2,500) square feet which includes that hole in the approximate center of the square; or

Where a percolation test is required to determine the percolation rate for an alternative system, the percolation holes used to determine this rate must be located at the intersection of lines in a grid pattern with maximum perpendicular distances of twenty-five (25) feet between the lines of the grid. Each hole shall be considered reasonably representative of a square area of six hundred twenty-five (625) square feet, which includes that hole in the approximate center of the square.

Where percolation tests are used to determine the rate at which water moves through the soil, the minimum lot size shall be twenty thousand (20,000) square feet where a public water supply is used or a minimum of twenty-five thousand (25,000) square feet where a private water supply is used. The Department shall be notified at least three (3) days prior to the day that the percolation test will be conducted. Percolation test procedures may be monitored when deemed necessary.

(i) Two (2) copies of the subdivision plat at a scale of one (1) inch equals one hundred (100) feet shall be submitted to the Commissioner. Such plat shall show percolation test holes iden tified by number and plotted to scale, subdivision boundaries and other perti nent topographic features. All lot and grid lines shall be drawn with appropriate numbers shown on the plat corresponding with survey stakes on the ground.

(ii) Tabulated results of percolation test holes shall be reported on a form provided by the Department.

(iii) The actual average percolation rate shall be determined by averaging only the test results from the area actually to be covered by the permit, which includes both initial and duplicate area. Areas in which percolation test results were unfavorable shall be excluded. The average percolation rate shall be calculated on a weighted basis.

(iv) Percolation test results shall not be conclusive evidence as to the suitability of an area. Such tests shall be considered and analyzed as one of the many criteria in determining site suitability.

3. All percolation test locations shall adhere to the requirements of paragraph (1) of Rule 0400-48-01-.11.

(4) Construction Design

(a) Each lot shall be accurately surveyed and lot boundaries designated by survey stakes with lot numbers shown on said stakes.

(b) Three (3) copies of a subdivision plat at a scale of one (1) inch equals one hundred (100) feet shall be submitted to the Commissioner, which shall indicate:
1. Lot dimensions with all lots numbered.

2. Easements for any purpose.

3. Surface and underground drainage designed so as not to interfere with subsurface sewage disposal systems.

4. Positive drainage plan, where needed. A positive drainage outlet must be available for each lot requiring soil improvement practices before the final plat is signed. If construction of a positive outlet is necessary, all construction shall be done before final plat approval is given. Off property easements may be necessary.

5. Seal and signature of registered surveyor. (In order to survey and plat subdivisions an engineer, by law, must be a registered surveyor).

6. Precision of the unadjusted survey. A minimum ratio of precision of the unadjusted survey of 1:7,500 is required.

7. Vicinity map.

8. North arrow indicating magnetic north or otherwise and indicate the scale of the plat.

9. All final plats shall have distances on all lines and shall indicate the identity of all corners such as steel post, concrete or iron pin.

(c) The submittals required by paragraphs (3) and (4) of this rule may be combined into one (1) submittal to the Commissioner.

(d) After review of the site and information submitted, the Commissioner shall:
1. Approve in writing the subdivision as proposed, or

2. Recommend in writing the corrections needed to receive approval, or

3. Indicate in writing that the proposed subdivision or areas therein are not suitable with reasons therefore.

(e) Where revisions are made to the construction design, revised plats shall be submitted to the Commissioner.

(5) Additional Data

Whenever the data required in these rules are insufficient to determine suitability of an individual lot or subdivision, the Commissioner may require additional data.

(6) Final Approval

(a) Two (2) copies of the final plat shall be submitted to the Commissioner with permanent lot lines drawn and the information required by subparagraph (3)(a), subparagraph (3)(b), and paragraph (4) of this rule. Additional plats for recording purposes without soil delineation, contour lines and percolation test hole locations may be submitted for approval.

(b) The estimated wastewater flow or number of bedrooms for each lot shall be shown on the plat.

(c) Any subdivision plat may be subject to restrictions as determined by the Commissioner and such restrictions shall be recorded on the plat. This may include designation of primary and duplicate areas or soil area to be reserved for subsurface sewage disposal systems.

(d) The Commissioner may approve a plat by attaching an appropriate signature after all provisions of these rules are met.

(e) Before any changes or restrictions can be made or removed, a revised plat must be submitted to the Commissioner in order to maintain plat approval.

(7) Individually owned lots in unapproved subdivisions shall meet the requirements of this rule with the exception that only one copy of each plat shall be submitted to the Commissioner, with the plat representing only the individual lot. Where a plat of the unapproved subdivision has been recorded, this rule shall only apply to those subdivisions recorded after June 30, 1995.

Authority: T.C.A. §§ 68-221-401 et seq. and 4-5-201 et seq.

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