Design flow calculations for dwellings shall be based on the total
number of rooms in the dwelling and not necessarily on the number
of proposed bedrooms. The number of bedrooms shall be calculated in
accordance with the State Sanitary Code, 310 CMR 15.002. The plan
shall clearly state the total number of habitable rooms in the dwelling
(not including hallways, bathrooms, unfinished basements or unheated
areas). Rooms that could easily be converted into a bedroom shall
be included in the room count. A deed restriction may be required
if the number of habitable rooms exceed the calculation for bedrooms
for the dwelling.
All soil absorption systems connected to a vent shall be equipped
with a suitable air filtering system for odor control. Vents shall
have a minimum setback to an abutting property line of five feet.
Profile and cross sections shown on the plan must show clearly the
existing and proposed soil conditions, limits of excavation and fill
replacement and graphically show the test pit data, percolation test
data and estimated seasonal high water table (ESHWT) beneath all components
of the system.
Bench marks used to establish site elevations shall be clearly delineated
on the plans. Bench marks established shall be constructed so as to
be permanent and easily identified in the field. Plans shall be generated
from elevations that correspond to NGVD datum or other datum that
is consistent with elevations determined for already established site
plans or subdivision plans. Plans submitted for isolated lots that
have no reference to vertical datum may use an established permanent
bench mark provided it can be easily found in the field, is clearly
identified on the plan, and is established so as to be a permanent
object which will be existent in future years.
The applicant shall provide plans, profiles, cross sections, construction
notes and test hole data, in accordance with the Design Checklist
for Wastewater Disposal System found in the back of these regulations.[1]
All on-site wastewater disposal systems that require pumping into
the leaching facility shall be designed as a pressure distribution
system utilizing a central manifold and lateral piping network or
shall be designed to flow by gravity from the distribution box to
the leaching field.
Use of mercury pump floats is prohibited. Mechanical pump floats
are acceptable. When an existing pump system is to be replaced or
removed, mercury pump floats shall be removed and properly disposed
off in accordance with the law.
If the design flow exceeds 2,000 gallons per day, then the soil absorption
system shall be divided into two separate leaching systems, each capable
of supporting 1/2 of the design flow.
A maintenance contract shall be provided to the BOH prior to issuance
of the certificate of compliance.
The BOH reserves the right to request the applicant, in certain
circumstances, when public health and safety may be at compromise,
to provide information for the use of an alternative system as a means
of onsite wastewater disposal system.