HomeMy Public PortalAboutBMP O&M_FINAL_2022.06.22Maintenance Costs
Maintenance costs vary depending on drainage
area, storage volume, and type of stormwater BMP
technology in place. O&M costs are estimated to
be 10% of total construction costs for BMPs costing
$10,000 and 5% of those costing $100,000. While
exact cost of maintenance is site specific and diffi-
cult to estimate, it is important that BMP owners
allot funds for maintenance.
Do's and Don'ts of Private
Stormwater BMP Ownership
Do expect BMPs to collect sediment, trash, and
other pollutants that need to be properly disposed
of.
Do expect BMPs to temporarily hold water as de-
signed.
Do expect the vegetation in your BMPs will require
routine maintenance.
Do not alter the drainage area and overland flow
path carrying stormwater to your BMP.
Do not ignore eroding areas in your BMPs.
If not addressed, these issues will limit the effec-
tiveness of your BMP to hold and treat stormwater.
Post-Construction
Stormwater Best
Management
Practices (BMPs)
Ownership and
Maintenance
The ABC's of Private Post-Construction
Stormwater BMP Ownership
Always receive a copy of the SWMFR, which
outlines BMP operation and maintenance
activities, at the time of purchase of the property.
Budget for maintenance, routine and non-routine,
as outlined in your maintenance schedule. Costs
vary per BMP technology installed.
Check-up on your stormwater BMP. Regular
inspections and routine maintenance will minimize
the need for major repairs.
MSD Project Clear
Division of Environmental Compliance
10 East Grand Avenue
St. Louis, MO 63147-2913
Phone: 314.436.8710
MSDProjectClear.org
Find us @MSDProjectClear
For more information on BMP ownership
and maintenance, visit our Maintenance
Responsibilities webpage by scanning the
QR code below.
Photos by Megan Ross
Metropolitan St. Louis Sewer District Project Clear MSDProjectClear.org MSD Customer Service: 314.768.6260
What is a BMP?
Post-construction Stormwater Best Management Prac-
tices (BMPs) are private stormwater facilities used to
prevent or reduce the pollutants in stormwater runoff.
The St. Louis County Phase II Stormwater Manage-
ment Plan (SWMP) addresses potential sources of
pollutants in stormwater as required by federal and
state regulations. Accordingly, these stormwater man-
agement facilities are required in all new development
and redevelopment projects designed after 2006. De-
tention basins have been required since the late
1980's. Post-construction BMPs and detention basins
are installed to retain and/or treat a specified volume
of stormwater at the site. Post-construction storm-
water BMPs are required to be maintained by the
owner of the property or trustee association for those
installed on common ground.
Types of BMPs
The two basic categories of post-construction storm-
water BMPs are structural and non-structural.
Structural Stormwater BMPs such as rain gardens
and filtration systems are physical devices designed to
capture and/or treat stormwater at its source. Many
structural stormwater BMPs mimic natural systems,
and rely upon vegetation and soil mechanisms in or-
der to perform as intended. These are considered
"green" infrastructure systems. All BMPs must be
maintained so they will always perform as they were
designed to, to reduce runoff volume and remove
pollutants from stormwater.
Non-structural Stormwater BMPs focus on preserv-
ing open space, protecting natural systems, and incor-
porating existing landscape features, such as wetlands
and stream corridors, into a site plan to manage rain-
water at its source. These areas must be maintained as
designed in perpetuity.
Bioretention (i.e. Rain Gardens)
Permeable Pavement
Hydrodynamic Separators
Sand and Organic Filter Systems
Infiltration Trenches
Wet and Dry Grass Swales
Wetlands/Wet Ponds
Rain Harvesting Cisterns
Green Roofs
Examples of Structural BMPs:
Amended Soils
Natural Area Conservation
Buffer Zones
Low Impact Development (LID)
Open Channel Use
Rooftop Disconnections
Non-Rooftop Disconnections
Examples of Non-structural BMPs:
Private BMP Owner Responsibilities
Maintenance
Generally, BMP maintenance falls into two categories:
routine maintenance and non-routine (repair) mainte-
nance. A Stormwater Management Facilities Re-
port (SWMFR) was written for each BMP by the de-
sign engineer. It is the owner's handbook to BMP
ownership. It outlines all routine maintenance and
inspection activities that are required.
A Maintenance Agreement with MSD Project Clear is
signed by the property owner prior to site design ap-
proval. This document is a formal agreement from the
property owner to maintain the BMP in perpetuity.
Failure to maintain BMPs is a violation of MSD Ordi-
nance No. 15048. The BMP owner is responsible for
coordinating proper restoration of BMPs if needed.
For example, if utility work is needed within the BMP
reserve area, the BMP owner must ensure the BMP is
properly restored by the entity performing work in the
area.
Regular routine maintenance, and from time to
time non-routine maintenance, will increase the
longevity of a BMP and ensure it continues working
as designed.
Inspections
Inspection frequency varies according to BMP type
and site conditions. Routine inspections should be
completed as outlined in the SWMFR. Inspections
along with any corrective actions taken should be
documented. The effectiveness of post -
construction stormwater BMPs depends upon
regular inspections. MSD inspectors may also
periodically inspect the BMP. Inspection checklists
can be found on MSD’s website (see QR code on
back).
Annual Reports
BMP owners are required to submit an Annual BMP
Maintenance Report to MSD by March 31st of the
following year. The Annual Report must provide
documentation that maintenance was performed in
accordance with the SWMFR. Annual reports should
be submitted online, and a link to the form is
available at our Maintenance Responsibilities
webpage (see QR code on back). The online form
will ask the owner to submit information about the
condition of each BMP for the project, records of
any maintenance that was performed, and at least
one photo for each BMP on site.