# Subdivision 2. Individual Sewage Disposal Systems

Codified through Bill No. CB-018-2026, adopted May 12, 2026, effective July 24, 2026. Source: Municode, Supplement 2026 Update 2. Editorial notes and legislative history omitted.

## Subdivision 2. Individual Sewage Disposal Systems

### Sec. 22-122. Minimum lot size

Prince George's County, Md., Code § 22-122 (2026)

The minimum lot size shall depend upon the site plan, the percolation test conducted on the lot and be in accordance with COMAR 26.04.03 and the Prince George's County Ten Year Water and Sewerage Plan. Lot size shall not prohibit the remodeling of an existing system that has failed under normal use.

### Sec. 22-123. Recovery Area

Prince George's County, Md., Code § 22-123 (2026)

(a) The recovery area of the building site must meet the requirements of the Ten Year Water and Sewerage Plan and COMAR 26.04.03. The recovery area must remain undisturbed and be free of permanent structures, easements, driveways, utility lines, or other physical structures that would prohibit the installation of future replacement drainfields.

(b) The recovery area, as shown on the approved site plan, as well as the septic system, shall remain as part of the lot until such time as the building is connected to public sewer, except as provided for in the Prince George's County Ten Year Water and Sewerage Plan.

### Sec. 22-124. Percolation tests

Prince George's County, Md., Code § 22-124 (2026)

(a) A completed application or form provided by the Health Department for percolation tests must be filed with the Health Department specifying the following information:

  (1) Owner's name, address, and telephone number;

  (2) Applicant's name, address, and telephone number;

  (3) Proposed use of the building;

  (4) Number of people to be served by this building;

  (5) Square footage of proposed building;

  (6) Residential use: number of bedrooms, basement plumbing anticipated;

  (7) Commercial use:

    (A) Fixture count by type and number;

    (B) Type of operation;

    (C) Number of employees;

    (D) Type of waste expected to be discharged;

  (8) Other pertinent information as may be necessary.

(b) A proposed site plan must accompany any commercial application specifying the proposed building site, property lines, proposed parking lot, and two (2) foot contours.

(c) A site plan may be required for subdivisions showing the house locations, proposed wells (if applicable), five (5) foot contours, and property lines for each lot.

(d) On lots where the Prince George's County Soil Survey maps or soil borings indicate severe limitations based on seasonally perched, seasonally high water tables, or flood hazards, soil percolation tests and any other tests, as may be required, shall be performed from February 1 - April 30 when the highest water table can be expected at the on-site sewage disposal site. The time period can be expanded or restricted by the Health Officer depending on the static water levels observed in water table wells located throughout the County. If the Health Officer or a professional soil scientist certified by the American Registry of Certified Professionals in Agronomy, Crops, or Soils (ARCPACS) finds that the soil conditions found at the on-site sewage disposal site are contrary to the County Soil Survey and that seasonably high water tables, perched water tables or flood hazards do not exist, the percolation test may be conducted at any time.

(e) Property Identification and Water Table Observation Hole.

  (1) The applicant shall locate the property lines and proposed building on the site.

  (2) A water table observation hole shall be required from which the static groundwater level shall be determined after a twenty-four (24) hour observation period. The hole shall be located within the proposed recovery area. Subsequent percolation tests shall be conducted in the absorptive layers a minimum distance (buffer) above the determined groundwater table as determined in Table 1 of Appendix B (Section 22-152).

  (3) The Health Department is responsible for approving the proposed location of all percolation tests and water table observation holes.

(f) Shallow Test Procedures (less than five (5) feet).

  (1) Dig or bore a minimum of four (4) test holes with a diameter from four (4) inches to twenty-four (24) inches and vertical sides to the depth of the proposed absorption trench.

  (2) Preparation of test holes.

    (A) Remove any smeared soil surfaces and provide a natural soil interface into which water may percolate. Remove all loose material from the hole. Add two (2) inches of coarse sand or fine gravel to protect the bottom from scouring and sediment.

  (3) Prewetting and test measurement.

    (A) Fill the hole with clean water so that the water level is approximately six (6) inches over the gravel. Measure the drop every thirty (30) minutes, readjusting the water level to six (6) inches above the gravel for two (2) hours. The last measurement observed will determine the percolation rate and shall be recorded as the time in minutes for the water to drop one (1) inch. If the water level in the hole fails to drop the minimum amount in Table 2 (Section 22-153) within a thirty (30) minute period, the hole is unsatisfactory. A more extensive prewet may be required in clayey soils.

    (B) Minimum requirement.

      (i) A test shall be satisfactory when the percolation rate is demonstrated to be at least .2077 gallons per square foot which is equivalent to the required minimum Maryland State Standard percolation rate of one (1) inch in thirty (30) minutes, based on a one (1) foot square test hole. Percolation rates for round percolation test holes can be found in Table 2. (Section 22-153).

    (C) In soils in which the first six (6) inches of water seeps away in less than thirty (30) minutes, the time interval between measurements shall be ten (10) minutes for a maximum of forty (40) minutes. The drop that occurs during the final ten (10) minutes is used to calculate the percolation rate.

(g) Deep Testing Procedures (five (5) feet or greater).

  (1) Number and location of tests.

    (A) Test holes eight (8) inches to twenty-four (24) inches in diameter shall be bored to a depth where absorptive soil conditions are observed. A minimum of two (2) satisfactory tests shall be conducted to establish adequate disposal area. If deemed necessary, additional tests, or soil borings may be called for.

  (2) Prewetting and Percolation Rate Measurement.

    (A) Procedures.

      (i) The test boring shall be filled with a minimum of four (4) feet of water at which time the water level is allowed to drop a prescribed amount of inches as specified in Table 3 (Section 22-154). After the water level has dropped the prescribed number of inches, the water level is adjusted back to its original level and the procedure is repeated. A more extensive prewet may be required at the discretion of the Health Officer. The last measurement observed will determine the percolation rate and shall be recorded as the time in minutes for the water to drop one (1) inch. If the water level within any of the holes fails to drop the prescribed amount of inches within a thirty (30) minute time period, the hole is considered unsatisfactory.

    (B) Minimum requirement.

      (i) A test shall be satisfactory when the percolation rate is demonstrated to be at least .2077 gallons per square foot which is equivalent to the required minimum Maryland State Standard percolation rate of one (1) inch in thirty (30) minutes, based on a one (1) foot square test hole. Percolation rates for round percolation test holes can be found in Table 3 (Section 22-154).

(h) Supplementary percolation tests may be required by the Health Officer if needed.

(i) Grading and filling of the sewage disposal area may negate the percolation test. Grading and filling of the proposed sewage disposal and recovery area will not be permitted.

(j) Supplementary percolation tests may be required by the Health Officer after three (3) years from the date of testing, or if the percolation test requirements under which they were conducted are changed by new regulations.

(k) Once a proposed sewage disposal area has proven to be unsatisfactory due to unsatisfactory soil percolation rates, that area may not be retested at the same depth. Unsatisfactory water tables and percolation tests may not be included in the proposed recovery area.

### Sec. 22-125. General Design Requirements

Prince George's County, Md., Code § 22-125 (2026)

(a) The design of the individual sewage disposal system shall take into consideration topography, water table, soil characteristics, available area, the quantity and type of sewage, the cost of constructing the system, projected sewage flow based on maximum occupancy of the structure, square footage of the structure, or other acceptable methods.

(b) The type of system to be installed shall be determined on the basis of location, soil permeability, and groundwater conditions, including depth to the water table.

(c) The system shall be designed to receive and treat all sewage, including wastes from garbage grinders and automatic washing machines, from the structures. Drainage from basement footings or from roofs shall not enter the system. In addition, wastes shall not be discharged into the system when their introduction would interfere with proper operation of the system.

(d) The treated wastes from a septic tank shall be discharged into subsurface disposal systems approved by the Health Officer.

(e) The minimum distances that shall be observed in locating the various components of the individual sewage system from other structures shall be as indicated in Table 4 (Section 22-155).

(f) Under unusual circumstances, the Health Officer may approve variances to the design criteria, or may require the installation of special sewage disposal components such as alternating drainfields, low pressure distribution, diversion valves or dosing when appropriate.

### Sec. 22-126. Construction Specification

Prince George's County, Md., Code § 22-126 (2026)

(a) Individual sewage disposal systems must be designed, constructed, altered, extended or enlarged, or remodeled in accordance with the requirements set forth in this Subdivision.

(b) The building sewer shall be constructed in accordance with the Washington Suburban Sanitary Commission plumbing regulations.

(c) Septic tanks shall meet the following specifications:

  (1) The septic tank shall have a capacity of not less than that shown in Table 5 (Section 22-156).

  (2) In tanks having two (2) compartments, the inlet compartment shall have a capacity between one-half (1/2) and two-thirds (2/3) of the total tank capacity. If an inverted fitting is used on the inlet compartment side of the baffle, its opening shall be located forty (40) percent of the liquid depth below the flow line. In each case, the total area of the opening provided by the pipe fitting shall be equal to, or greater than, the area of the inlet to the tank.

  (3) Septic tanks shall be constructed of reinforced concrete, or other material approved by the Health Officer, and be of permanent construction. Precast concrete tanks should have a minimum wall thickness of three (3) inches and should be adequately reinforced. The cover of the tank shall be designed for a dead load of not less than three hundred (300) pounds per square foot and, if of concrete, should be reinforced and not less than three (3) inches thick. Septic tanks which are subject to vehicular loadings shall be constructed of reinforced concrete adequate to withstand the loadings.

  (4) The inlet and outlet of the septic tank shall be provided with manholes. Each compartment in multiple compartment tanks shall be provided with a manhole. Manhole openings shall be at least twenty (20) inches in minimum dimension and provided with covers which can be sealed watertight. Manhole extensions shall be required where necessary to provide access for maintenance to the septic tank and be so constructed to be watertight.

  (5) Pipe inlets shall be installed consisting of a sanitary tee of cast iron, PVC, or other material as authorized by the Washington Suburban Sanitary Commission plumbing regulations. Outlets may be sanitary tees of cast iron, vitrified clay pipe, plastic or other acceptable material. Short sections of pipe shall be installed in the tees to the required outlet depths. Baffles may be installed when approved by the Health Officer.

  (6) The invert of the inlet pipe shall be located at least two (2) inches above the invert of the outlet.

(d) Construction Standards for Absorption Trenches.

  (1) The minimum absorption trench length shall be calculated according to Appendix A (Section 22-150).

  (2) The trench shall be filled with filter material to a level two (2) inches above the distribution line. The filter material shall cover the tile and extend the full length, width and depth of the trench and be not less than six (6) inches below the tile and two (2) inches over the tile. The filter material shall be washed gravel or other material approved by the Health Officer ranging in size from one and one-half (1 1/2) to two and one-half (2 1/2) inches. The filter material shall be reasonably free of fines, dirt, clays and other associated material and shall be covered by untreated paper or similar material one (1) foot from the top of the ground.

  (3) Distribution lines in absorptive trenches shall be constructed of ridged perforated plastic pipe that shall meet National Sanitation Foundation (NSF) Standard 14 or other material approved by the Health Officer. Each pipe must sustain a minimum pressure of twenty-five (25) psi and must have a minimum of three (3) rows of perforations with each row having three (3) perforations of three-quarter (3/4) inch diameter per lineal foot. The invert of each distribution line shall be installed approximately eighteen (18) inches below ground grade.

  (4) Absorptive trenches with depths of three (3) feet or less shall not be constructed on ground having a slope greater than ten (10) percent. Absorptive trenches with depths of greater than three (3) feet, but less than five (5) feet shall not be constructed on slopes exceeding fifteen percent (15%). Absorptive trenches with depths of five feet or greater shall not be constructed on ground with slopes in excess of twenty-five percent (25%).

  (5) All absorptive trenches shall be constructed at the same depth as the percolation test.

  (6) Absorption drainfields depths of less than five (5) feet will be spaced according to Table 6 (Section 22-157). Absorption drainfields depths of five (5) feet or greater will maintain a spacing of twice the gravel depth between drainfields up to a maximum of twenty (20) foot separation.

  (7) The distribution lines within one (1) absorption trench shall not exceed one hundred (100) feet in length. A one percent (1%) slope shall be maintained on the first twenty (20) feet of pipe while the remainder of pipe should maintain zero percent (0%) slope.

(e) Seepage Pits; specifications.

  (1) Absorptive area. Seepage pits may be installed where the absorptive strata is seventeen (17) feet or greater below grade.

  (2) Location. Seepage pits shall not be located in swales or ravines and shall not be installed on slopes exceeding twenty-five percent (25%).

  (3) Number of Pits. The number of pits shall be calculated based on the equivalent length of drainfield as determined by Appendix A (Section 22-150).

  (4) Depth of Excavation. The seepage pit excavation shall be constructed to the depth of the percolation tests.

  (5) Seepage pits shall be separated a minimum of twenty (20) feet from center to center.

  (6) The general construction of seepage pits shall be in accordance with Figure 1 (Section 22-158).

### Sec. 22-127. Privies; specifications

Prince George's County, Md., Code § 22-127 (2026)

(a) No person shall construct a privy for a structure served by a water supply under pressure. All privy pits shall be covered with a privy house, the floor and riser of which shall be constructed of concrete or tightly fitted wood. The riser shall be capped with a tight fitting, self- closing lid. The pit shall be vented through a screened stack extending from the top of the pit to above the roof of the house. Construction of the pit, floor, riser, seat and vent shall be such as to prevent flies and rodents from access to the pit contents. On request, a plan of a privy may be made available by the Health Officer. See Figure 2 (Section 22-159).

(b) At the discretion of the Health Officer, privies shall only be used in areas of the County where no other means of sewage disposal is available or in parks owned or operated by a governmental agency.

(c) Privies will not be approved for new construction except for campgrounds or at the discretion of the Health Officer. All privies, with the exception of vault privies, must be constructed so that the bottom of the privy pit shall meet minimum buffer requirements as established in Table 1 (Section 22-152).

### Sec. 22-128. Chemical Toilets

Prince George's County, Md., Code § 22-128 (2026)

(a) A chemical toilet may only be used as a method of sewage disposal under the following conditions:

  (1) As a temporary alternative for an existing building where water under pressure is not available until such time that a permanent means of sewage disposal is provided for that building;

  (2) For a temporary event not to exceed fourteen (14) days;

  (3) Building construction sites during construction;

  (4) At the discretion of the Health Officer, in parks owned or operated by a governmental agency.

(b) Chemical toilets must be maintained and emptied as necessary by a licensed scavenger to prevent a sewage disposal nuisance.

### Sec. 22-129. Holding Tanks; conditions; contract

Prince George's County, Md., Code § 22-129 (2026)

(a) Holding tanks shall not be used as a means of sewage disposal for new construction.

(b) The Health Officer may authorize the use of a holding tank as a method of sewage collection and disposal under the following conditions:

  (1) As a temporary means of sewage disposal during repair or remodel of an existing individual sewage disposal system.

  (2) As a interim means of sewage disposal where correction of a malfunctioning septic system is impractical until such time as a connection to public sewer can be made. The property must connect to the public sewerage system when it becomes available to the property.

(c) Prior to issuance of a permit for a holding tank the applicant shall submit to the Health Officer a copy of a valid contract with a licensed septic tank scavenger. The contract shall indicate that the holding tank will be properly cleaned and maintained during its use.

(d) The holding tank must be maintained and emptied as necessary by a licensed scavenger to prevent a sewage disposal nuisance.

### Sec. 22-130. Additional Requirements

Prince George's County, Md., Code § 22-130 (2026)

In the interest of preserving the public health, the Health Officer may, if necessary, impose more stringent requirements than provided in this Subdivision.