A. 
Horizontal separation distances.
(1) 
The following horizontal separation distances shall be maintained between the on-site disposal system plus recovery area and the features listed although greater distances may be required at the discretion of the approving authority.
Feature
Separation Distance
(I)
Steep slopes(>25 percent)
25 feet
(II)
Drainage and spring seeps
25 feet
(III)
Drainage ways and gullies
25 feet
(IV)
Floodplain soils
25 feet
(V)
Rock outcrops
25 feet
(VI)
Elevation of spillway crest water level in a water supply reservoir
300 feet
(VII)
Stream bank 3,000 feet or less upstream from a water intake on a water supply reservoir or intake on a stream used as a potable water supply
200 feet
(VIII)
Stream bank greater than 3,000 feet upstream from a water intake on a water supply reservoir or intake on a stream used as a potable water supply
100 feet
(IX)
Water bodies not serving as potable water supplies
100 feet
(X)
Water well system in unconfined aquifers
100 feet
(XI)
Water well system in confined aquifers
50 feet
(2) 
A lot located within 2,500 feet of the normal water level of existing or proposed water supply reservoirs, measured horizontally or within a 5,000-foot radius upstream from the water intake on streams used as potable water supply sources and a 5,000-foot radius of water intake located within a reservoir shall have an area of not less than 2 acres with a minimum width of 175 feet. An on-site sewage disposal system may not be located within 300 feet measured horizontally of the normal high water level of a water supply reservoir. Normal water level shall be the elevation of the spill way crest. These limitations do not apply to areas below the dam forming the reservoir.
B. 
Type of system. the type of private waste disposal system to be installed shall be determined on the basis of soil permeability topography and water tables.
C. 
Sanitary sewage. The private waste disposal system shall be designed to receive all sanitary sewage, including laundry waste, from the building. Kitchen disposal systems (garbage grinders) will not be permitted to discharge into a private waste disposal system. Drainage from basement floor, footings, or roof gutters shall not enter the waste disposal system. Waste from a water treatment system must be disposed of in a manner acceptable to the approving authority.
[Amended by Bill No. 14-10]
D. 
Design. The private waste disposal system shall consist of a septic tank, advanced pretreatment device or other approved treatment device, discharging via gravity or pump system into an approved system.
E. 
Grease interceptor. Grease interceptors are not necessary for installations at private dwellings. If included in the design of the private waste disposal system, it shall be installed on the kitchen line, outside of the building, before entering the building sewer leading to the treatment device. The trap shall be provided with a removable cover to permit access for removing the accumulated grease. The minimum liquid capacity shall be 1,000 gallons.
A. 
Location. The initial private waste disposal system and replacement system shall be located in the highest contours of the septic reserve area unless otherwise specified by the Health Department.
B. 
Distances. Table I provides for the minimum distances that shall be observed in locating the various components of the waste disposal system.
C. 
Design. The design of private individual waste disposal systems shall take into consideration the location with respect to private and municipal potable water supply wells and water systems or any other source of water supply topography water table, soil characteristics, available area and maximum occupancy of the building. There shall be provisions to accommodate adequate replacement systems until public sanitary facilities are available.
A. 
The building sewer which extends from approximately 5 feet beyond the foundation wall shall be connected to the treatment device by Schedule 40 or SDR #35 plastic pipe or other approved material, which shall be a minimum of 4 inches in diameter.
B. 
The slope of the building sewer 10 feet preceding the treatment device shall not exceed one-half inch per foot.
C. 
The building sewer must be constructed with material acceptable under the Plumbing Code. All joints are to be sealed in an approved method as prescribed within the Plumbing Code.
[Amended by Bill No. 14-10]
D. 
The building sewer should have a straight alignment, and bends are to be avoided wherever possible. Change in direction, horizontal or vertical, shall be made by use of long-radius one-fourth, one-eighth or one-sixteenth bends or Y-branches.
E. 
Cleanouts.
(1) 
Where the building sewer is greater than 75 feet in horizontal drainage, a cleanout shall be required.
(2) 
Cleanouts shall be installed at each change of direction of the building sewer greater than 45°.
(3) 
Cleanouts, when installed on an underground drain, shall be extended to or above the finished grade on either a plane of 45° or 90°.
(4) 
Schedule 40 or SDR #35 plastic pipe or approved plastic pipe shall be used for a cleanout pipe of the same nominal size in the drainage system. Cleanout plugs shall be of brass or approved plastic.
F. 
The building sewer shall in all cases be below the water supply line as required in the Plumbing Code.
[Amended by Bill No. 14-10]
A. 
Percolation tests are required to determine the absorptive capacity of the soil. All percolation tests shall be performed under the supervision of the Health Department on all lots where a private waste disposal system is required. Percolation tests will be conducted in the area as designated by the approving authority. Tests shall be made in sufficient number and at such locations as determined by the approving authority to assure a reliable determination of subsurface conditions.
B. 
A conventional soil percolation test shall consist of two parts: an observation pit and a soil test or time test. A soil percolation test is typically to be dug with a backhoe or other excavating equipment unless otherwise approved by the approving authority.
(1) 
The initial observation test pit is dug to 12 to 14 ft. or until a limiting horizon is encountered. A soil description and evaluation of the substratum conditions is recorded and the depth at which the time test can be conducted is determined. Not all sites are acceptable for the conduction of a time test and the installation of a conventional system.
(2) 
The percolation soil test hole shall be prepared by digging a hole one-foot square by one-foot deep on a ledge adjacent to or on a ledge at the end of the observation pit. The depth of the time test is determined after the excavation of the initial observation pit. The soil test hole must be dug in the porous absorption layer in which the system is to be installed.
(3) 
The bottom of the trench or tile field system shall be a minimum of 4 feet above the limiting horizon (rock > 50%, water table or other limiting horizon) or if no limiting horizon is encountered to the maximum depth of 4 feet above the bottom of the observation pit.
(4) 
Only the porous absorption area of the soil percolation test pit shall be considered in calculating the size of the system to be installed.
C. 
Single ring infiltrometer test or falling head percolation test measures the time required for a unit depth of water to infiltrate into the soil from a standard size infiltrometer (12 inch diameter cylinder). The test should be conducted only after a soil description including identifying limiting horizons, and water level data is recorded and the data indicates the required treatment zone is present and the site may be suitable. Representative tests shall be conducted in the least permeable horizon in the upper 24 inches of the soil. Single ring infiltrometer tests shall be performed for sand mound systems, at grade mounds and other shallow systems when appropriate. Testing must be in conformance with COMAR 26.04.02 and as described in the Maryland Department of the Environment (MDE) Site Evaluation Training Manual for On-Site Sewage Treatment and Disposal Systems.
D. 
Soil tests.
(1) 
A soil test consists of a two-inch drop of water level. The first inch, which is considered the presoaking time, shall not exceed 20 minutes.
(2) 
The time taken for the second one-inch drop is the recorded percolation test and is used in calculating the amount of square feet of absorption area that shall be required per 100 gallons of sewage effluent to be disposed. The second one-inch drop shall not exceed 30 minutes, except that when using innovative and alternative systems the percolation rate may be greater.
(3) 
The satisfactory soil test includes the following considerations: rate of water absorption, usable area, other nearby failing percolation tests, slope, size of initial system necessary sufficient area for replacement systems, failing private systems in the area and other related factors. The approving authority shall require that soil tests be conducted during certain periods of the year when moderate to severe conditions are expected according to the Harford County Soil Survey Maps and Interpretations as prepared by the United States Department of Agriculture Natural Resources Conservation Service or the Harford County Health Department experience.
E. 
Percolation tests may be generally considered invalid at any time when the approving authority has knowledge which indicates the test results are no longer accurate or test procedures have been altered sufficiently to render a significant change in the results. Additional percolation tests may be required.
F. 
After thorough soil testing of a parcel of ground and on finding the soil unsuitable for a private waste disposal system, the approving authority may consider such a parcel unsuitable for a private waste disposal system and may refuse to conduct additional soil tests.
G. 
Sewage waste disposal area requirements. All lots shall be required to record a minimum of 10,000 square feet or adequate repair area for an initial sewage waste disposal system and three repair waste disposal systems based on a four bedroom dwelling, whichever is greater.
[Amended by Bill No. 17-003]
(1) 
The corners of the septic reserve areas must be staked prior to a percolation test.
(2) 
A minimum of 2 test pits must be dug in the reserve area which is to be established on the lot. The Health Department may require additional test pits for a site to assure a reliable determination of subsurface conditions. A minimum of 2 test pits is required in the remainder or off-site easement reserve area. All percolation test holes are to be field located by an engineer/surveyor and submitted on a sealed (signed) plat.
(3) 
Preliminary percolation test results will be required for all moderate to severe rated soils. A minimum of one satisfactory preliminary percolation test per reserve area is required, as permitted by COMAR.
(4) 
The initial system shall be installed on the highest contour(s) of the disposal area unless an alternate site is approved, in writing, by the Health Department prior to construction.
(5) 
No grading is permitted in the septic reserve area or any area designated for on-site sewage disposal without written approval of the Health Department, and until all necessary permits are approved by the Department of Public Works, Sediment Control Division.
(6) 
Unless previously subject to an easement pursuant to the county's purchase of development rights program, the remaining land must have a restrictive covenant placed upon it to prevent additional or future development.
A. 
No septic tank shall serve more than 1 single-family dwelling or building for commercial use unless authorized by the Health Department.
B. 
Capacity. The capacity of the septic tank shall be in accordance with Table II.
C. 
Septic tanks shall have 2 compartments or consist of 2 tanks in series.
D. 
Construction. Septic tanks shall be constructed of corrosion-resistant materials and be constructed in a manner acceptable to the approving authority. Depending upon individual site conditions, top seam tanks may be required.
E. 
Manholes. The tank must be provided with a minimum of one manhole which shall be at least 20 inches square or in diameter with the opening exposing each compartment or two manholes, one over each compartment. Risers are to be installed over each manhole to the ground surface and shall be water tight.
F. 
Baffles. Baffles shall be installed on the inlet and outlet so as not to restrict the flow and shall extend to at least 6 inches above flow line. The inlet baffles shall extend 12 inches below the flow line and the outlet 15 to 18 inches below the flow line. On precast or poured concrete tanks, baffles shall be of precast or poured reinforced concrete or plastic.
G. 
Invert. The invert of the inlet pipe shall be 3 inches higher than the invert of the outlet pipe.
H. 
Septic tank standpipe. The septic tank standpipe will be inserted in the hole provided in the septic tank and extend to the surface of the ground as represented by the final grade. The standpipe extension will be approved plastic pipe or other approved material, with a tight-fitting cap.
I. 
Installation. The septic tank shall be installed in such a manner that the top shall not be more than 24 inches below the finished grade. Plumbing elevations must be carefully planned to fulfill this requirement.
J. 
The septic tank shall be installed in a manner to prevent flotation.
K. 
Alterations or changes in septic tank construction shall be approved by the approving authority.
L. 
All voids, joints and openings shall be properly sealed to make the septic tank watertight prior to final inspection.
M. 
Any septic system installed as part of new construction shall conform with COMAR requirements. The Health Department however may require the installation of best available technology for removal of nitrogen (BAT) standards in a lot outside of the Chesapeake Bay Critical Area should circumstances affecting public health be involved.
[Added by Bill No. 14-10; amended by Bill No. 17-003]
A. 
A distribution box or boxes shall be required for all gravity fed flow systems.
B. 
Locations. The distribution box shall be located on solid ground at least 5 feet from the septic tank and minimum of 5 feet from any absorption system.
C. 
Construction. The distribution box shall be of watertight construction and must be constructed in a manner acceptable to the approving authority.
D. 
Invert level. The invert of the inlet pipe shall be located 2 inches above the invert of the outlets to each distribution line.
E. 
Baffle. Every distribution box shall have a baffle or similar device, acceptable to the approving authority at least 6 inches high and extending two-thirds across the bottom with equal open spaces between ends of baffle and side walls of the box. The baffle shall be firmly set on the bottom of the box, shall be placed at right angles to the direction of the incoming flow and shall be placed a minimum of 6 inches from the inlet.
F. 
Connections. The distribution box shall be connected to the septic tank or other treatment device by approved pipe with a watertight seal at both ends. A watertight four-inch solid pipe shall be used to convey the septic effluent from the distribution box to the absorption system. All connections to the distribution box shall be sealed to prevent any seepage from the box. If more than 1 outlet port is utilized, the flow shall be balanced by the use of levelers. All unused outlet ports shall be properly sealed.
A. 
Minimum standards. The minimum standards for the construction of all subsurface drainage disposal systems shall be shown in Table III.[1]
[1]
Editor's Note: Table III is included at the end of this chapter.
B. 
Size and requirements. Size requirement for subsurface drainage disposal systems shall be in accordance with.
(1) 
Loading rates: maximum loading rates for individual residences, commercial establishments and institutional establishments using standard trench, deep trench or seepage pit disposal techniques with an accumulative peak flow less than 5,000 gallons per day.
Percolation Rate
(in minutes for 1 inch
drop after prewetting)
Maximum Loading Rate
(gallons/day/sq.ft.)
2-5
.9
6-10
.8
11-15
.7
16-20
.6
21-25
.5
26-30
.4
(2) 
Absorption area for standard trenches, deep disposal trenches or seepage pits (see below).
(3) 
Flow.
(a) 
For residential use, 150 gallons per day per potential bedroom shall be used as the minimum design flow.
(b) 
For commercial, industrial or institutional establishments, the approving authority may approve design flows based upon actual flow measurements or estimated flows for square footage or plumbing fixtures developed for similar establishments. In no instance shall design flow be less than 400 gallons per day.
C. 
Each disposal trench shall be connected by a watertight line from the distribution box to the trench. No disposal trench shall be subdivided.
D. 
Filter material. The filter material shall not be less than 12 inches in depth below the drain pipe and shall extend the full width of the trench. After installation of the drain pipe, additional filter material shall be placed surrounding and over the drain pipe to a depth of not less than 2 inches. Filter material shall consist of washed gravel, crushed stone or like materials ranging in size from one-half inch to two and one-half inches in diameter and free of all fines, dust, ashes, clay and other debris.
E. 
Filter material cover. Filter material cover may consist of hay straw red resin, geo textile fabric or building paper with width and length of the trench. Asphalt-treated paper shall not be used.
F. 
Backfill material. Backfill material shall be select earth fill and shall be free of clay inert.
G. 
Standard trenches: Absorption area for standard trench is determined by acceptable bottom area only. The length of trench required is determined utilizing the following formula.
[Amended by Bill No. 14-10]
(f ÷ l) ÷ w = length of trench
Where:
f
=
maximum daily flow
l
=
loading rate
w
=
width of trench in feet
H. 
Deep disposal trenches: absorption area for a deep trench system is determined by the acceptable bottom area and the depth of usable side wall area on the basis of percolation tests, observation of the soil profile at various soil depths and other hydrogeologic data, as may be required by the approving authority. The length of deep trench required will be based on the following methods.
[Amended by Bill No. 14-10]
(1) 
Calculate the length of standard trench.
(2) 
Calculate the percent of length of standard trench utilizing the following formula.
[(w + 2) ÷ (w + 1 + 2d)] x 100
Where:
w
=
width of trench in feet
d
=
depth of gravel in absorptive material below disposal pipe in feet
(3) 
Multiply the standard trench length by the percent of length of standard trench.
I. 
Seepage pit. Absorption area for a seepage pit is based upon the depth of the seepage pit in absorptive material. Calculate available absorptive area based on percolation and other site data using the following formula.
The available absorptive area in the seepage pit is multiplied by the appropriate loading rate to obtain the absorptive capacity in gallons. If the seepage pit is inadequate in size based on the maximum design flow the proposed design will have to be modified by either increasing the number of seepage pits, increasing the diameter of the seepage pit or a combination. The combined absorption area from all seepage pits must equal or exceed the design flow.
(1) 
Seepage pit. Seepage pits may be used when approved by the Health Department either to supplement the subsurface disposal field or in lieu of such disposal field where soil conditions and topography favor the operation of such pits. The minimum standards for the construction of seepage pits shall be shown in Table III.[2]
[2]
Editor's Note: Table III is included at the end of this chapter.
(2) 
Size. The capacity of a seepage pit is to be computed on the basis of loading rate and absorption area based on percolation tests and site data.
(3) 
Filter material. The annular space between the original soil and the rings shall be filled with an approved filter material.
(4) 
For filter material cover, see Subsection E above.
(5) 
For backfill material, see Subsection F above.
(6) 
Seepage pit cover. A reinforced concrete cover a minimum of 4 inches in thickness shall be required. A six-inch diameter hole shall be provided to accommodate a six-inch approved cleanout pipe.
(7) 
Seepage pit cleanouts. The cleanout shall extend to finish grade and be provided with a tight-fitting cap.
J. 
Sand mounds: Sand mound systems shall be designed and constructed in accordance with COMAR 26.04.02.
In any instance where sewage effluent from an individual waste disposal system is to be discharged onto the surface of the ground or into the waters of the state, final approval of the proposal, including the issuance of a point of discharge, shall be subject to the policies of the Maryland State Department of the Environment.
A. 
The Department of the Environment and the approving authority shall consider all possible methods for correcting existing system failures and providing facilities for homes which lack indoor plumbing and, based on a case by case evaluation, provide the best technical guidance in attempting to resolve existing pollution or public health problems. When a public sewer is not available and a conventional on-site system design cannot alleviate the problem or does not provide the best method of correction, innovative or alternative technology may be used.
B. 
Alternative technology may also be used for new construction. The use of non-conventional on-site sewage disposal systems on new construction where site limitations preclude the use of conventional on-site disposal systems shall be reviewed and approved using professional judgement. The soil properties and ground water condition at the proposed site shall demonstrate adequate support for successful use of the proposed system as an alternative to conventional on-site sewage disposal system.
C. 
Non-conventional on-site sewage disposal systems may not be considered as acceptable on-site sewage disposal systems with regard to the subdivision of land pursuant to COMAR 26.04.03.
D. 
holding tanks.
(1) 
May be used for re-construction of structures when community sewer facilities are not available and on-site repair is not possible, only if the structure was legally situated and legally occupied within 3 years of the date of application. In no case should the reconstruction result in an increase in square footage or estimated daily sewage flow to the proposed structure compared to proven historical use. A variance to the 3 year limitation may be granted on a case by case basis in consideration of the following:
(a) 
The proposed structure is to be owner-occupied.
(b) 
The owner can demonstrate a historical use and occupation that was interrupted by events beyond the control of the existing and past owners.
(c) 
The owner can demonstrate that in the past the property obtained approvals for an on-site sewage disposal system or holding tank from the approving authority.
(d) 
The structure in question is to be the only structure located on the property.
(2) 
Holding tanks shall be sized to hold a minimum of 7 days' effluent and shall be of watertight construction. The contents shall be regularly removed and disposed of in accordance with Harford County requirements. A high effluent level alarm system shall be required on all holding tanks. Adequate access must be made available to allow for pump-outs on a regular basis.
(3) 
The applicant shall submit along with the application, a maintenance contract acceptable to the approving authority which shall include an acceptable pumping schedule between the applicant and an approved liquid waste hauler. Copies of all pumping receipts are to be made available to the Health Department upon request. Upon cancellation of the contract the hauler and the owner are jointly responsible for notifying the Health Department.
(4) 
The applicant shall sign an agreement with the approving authority containing the above conditions. The agreement shall run with the property and be binding on all future owners of the property.
A. 
Privies. Privies will not be approved for new construction except at the discretion of the Health Officer.
B. 
Chemical toilets. Chemical toilets may be used as a method of sewage disposal under the following conditions.
(1) 
For a temporary event not to exceed 14 days.
(2) 
Building construction sites during construction.
(3) 
At the discretion of the approving authority other situations may be allowed on a temporary basis.
(4) 
Chemical toilets must be maintained and emptied as necessary by a licensed liquid waste hauler to prevent a sewage disposal nuisance.
(5) 
The requirements of this chapter do not preclude or limit modifications to system design or installations as deemed appropriate by the approving authority.