Mt. Pleasant ​Township, Westmoreland county

Mt. Pleasant Stormwater Information

​​Mt. Pleasant Township recognizes that storm water is a very important natural resource that provides a source for our drinking water supplies, water for our crops, lawns and gardens, and a replenishment of our streams, ponds and lakes which in turn provide recreation opportunities and enhanced aesthetic value to our community. In order to protect our natural waterways, Mt. Pleasant Township has implemented a program to regulate the storm water that is intercepted by its municipal separate storm sewer system, or MS4.

This program was initiated by a state-wide mandate for small- to medium-sized communities with MS4s, such as Mt. Pleasant Township, to be permitted under the Pennsylvania Department of Environmental Protection’s (PADEP’s) National Pollution Discharge Elimination System (NPDES) Phase II permit program. This webpage provides general information on storm water and on the Township’s MS4 stormwater program.


What is an MS4?

MS4 is an acronym for a Municipal Separate Storm Sewer System.  An MS4 is defined as a collection and conveyance system or a group of collection and conveyance systems owned, operated and maintained by a state, city, township, borough or other public entity.  An MS4 collects and conveys only storm water runoff and conveys it into streams, rivers, lakes, wetlands or other natural or man-made receiving waters within the Commonwealth of Pennsylvania.

The MS4 system may include such structures as storm pipes, catch basins, storm manholes, trench drains, roadside swales and cross drains, conveyance channels, detention ponds, infiltration basins, rain gardens or other structures designated for the collection, storage and conveyance of stormwater runoff.


What is Stormwater Runoff?

Stormwater runoff is water from rainfall, snowmelt, and/or ice melt that flows over ground or across impervious surfaces (streets, parking lots and rooftops) and does not infiltrate into the ground.  Stormwater runoff may flow directly into natural waterways or it may be intercepted and collected by the Township’s municipal separate storm sewer system where it is then discharged at discrete locations referred to as outfalls into the natural waterways.


What is Non-Stormwater Discharge?

Non-stormwater discharge is discharge into the Township’s MS4 system or natural waterways that is not rainfall or snowmelt.  Non-stormwater discharge includes groundwater exfiltration, mine pool discharge, discharges from potable water sources such as fire hydrants or waterline blow-off valves, sanitary sewer discharges, septic systems, or combined sanitary and storm overflows.  The Township’s stormwater management ordinance prohibits illicit discharges and connections into its MS4 but does list certain exemptions for non-stormwater discharges.


Why Can Stormwater Runoff Be A Problem In The Township?

As stormwater runoff flows over lawns, roadways, parking lots, or land disturbed by construction activities, it accumulates chemicals, oils and grease, debris and litter, sediment, heat or other pollutants that contaminate and adversely affect the water quality of our natural waterways.

Also, as more impervious cover is constructed or as natural vegetation is cleared and the underlying soil is compacted, more stormwater runoff is generated.  Stormwater runoff pollution can lead to deterioration of the quality of our natural waterways which are used for fishing, swimming, boating, as well as sources of our potable water supply.  Increases in stormwater volume can lead to accelerated stream bank erosion and more frequent flooding which can result in damage to and loss of property as well as premature failure of roadways, bridges, and other infrastructure.


What is Mt. Pleasant Township Doing About Stormwater Runoff?

As part of its MS4 permit program, the Township has implemented several actions required under the NPDES storm water program, permittees must develop a stormwater management plan that provides the details of how the community will comply with the requirements of the permit. Permits are based on six minimum control measures, or MCMs, to ensure the proper handling and discharge of stormwater through its MS4 system.  Such measures include:

MCM #1 – Public Education & Outreach
An informed community is a very important part of a stormwater management program to insure support and compliance. For this measure the township is providing and distributing educational materials concerning stormwater runoff through various outlets to residents, businesses, contractors and developers within the Township. Storm drain markers are also important to remind those passing by that the storm drains connect to local waterbodies and dumping will pollute those water, so you may start seeing these plaques on the inlets.


More information on MCM #1 is located here


MCM #2 – Public Participation/Involvement

The public is a valuable asset to a municipal stormwater management plan. The MS4 program can only be successful if the community around is willing to comply and be involved. The township is always looking for volunteers, including scouting groups, educators, outdoors clubs, watershed and environmental groups, or any individuals interested in keeping our streams and lakes clean.

For more information or ideas on how you can help out, call the Township at 724-423-5653 or follow this link.


MCM #3 – Illicit Discharge Detection and Elimination

Through its Illicit Discharge Detection and Elimination program, the Township has developed a Township-wide MS4 outfall map showing all natural waterways and roadways within the Township as well as all outfall locations of its MS4 system into the natural receiving waters.  This map will serve as a tool for the Township to identify outfalls that are discharging pollutants as determined by periodically conducting visual inspections of each outfall.  Any indications of non-stormwater discharge will prompt the Township to find and identify the source of these pollutants and take actions to eliminate the source(s).

The Township has adopted an ordinance to prohibit illicit discharges and connections of non-stormwater into its MS4 system and enable the Township the authority to fine individuals caught illegally dumping pollutants into its MS4 system.

For more information on illicit discharges follow this link.


MCM #4 – Construction Site Runoff Control

Polluted stormwater runoff from construction sites flows into the MS4 system and into the rivers and streams. The main pollutant concern is sedimentation. The Township has adopted an ordinance for the regulation of stormwater management of land disturbance activities and contractors need to be aware of the requirements and how to satisfy them.

For more information follow this link.


MCM #5 – Post Construction Runoff Control

The Township has adopted an ordinance for the regulation of stormwater management for the handling of stormwater runoff from a site after it has been developed.  The Township also provides educational material to developers and contractors who come to the Township office for building permit applications.

The Township also utilizes the technical support services of the Westmoreland Conservation District to review land disturbance plans to ensure that these plans are sufficient in addressing construction site stormwater and post-construction stormwater and to conduct site inspections to ensure that the sites are being constructed in accordance with the approved plans.

More information on MCM #5 is located here.


MCM #6 – Pollution Prevention and Good House Keeping

This is a crucial part of any MS4 program and by the township keeping their system clean it should encourage you to do the same. The Township is continuously maintaining and tracking its MS4 system through cleaning, repairing and improving the system to ensure that it is functioning correctly.

The Township is also monitoring all other municipal operations such as fleet vehicle maintenance, municipal property maintenance, as well as salt and anti-skid material stockpiling to minimize any detrimental impacts that these operations may have on the MS4 system.

More information on MCM #6 is located here.

What can residents of Mt. Pleasant Township do to improve stormwater quality in the Township?

It takes everyone to provide continual improvement to the waterways within Mt. Pleasant Township.  We would hope that every person realizes that what is dumped into the Township’s MS4 system, ultimately ends up in the streams, rivers and lakes that we all care about.  Here are several things each of us can do to help keep our waterways clean.

  • Do not dump any chemicals, oils or other automotive fluids, grease, pet waste, grass clippings or other yard debris, fertilizers, etc. into storm inlets, catch basins, roadside ditches or directly into stream channels.  This can lead to endangerment of the health of fish and other aquatic life, decrease in recreational opportunities and impairment of drinking water.
  • Have your vehicles serviced regularly to eliminate or minimize any leaks in your vehicle.
  • Do not litter or illegally dump.  Always dispose of any trash in its proper location and recycle whenever possible.  Car batteries can be turned it at most automotive parts stores.  Used motor oil and worn tires can be turned in at most auto service shops and auto parts stores.
  • Follow the instructions when applying fertilizers and pesticides to your lawn or garden and never apply these products immediately before a rain storm. Use fertilizers sparingly and use least toxic pesticides.
  • Vegetate bare spots in your yard and compost your yard waste. Also direct down spouts away from paved surfaces; consider a rain garden to capture runoff.
  • Notify the Township at 724-423-5653 to report any illegal dumping into the Township’s storm sewer system or natural waterways.


​Related Links and more information for the Township’s Stormwater Program



Stormwater Management Documents