Stormwater Management/ MS4 Information

Mount Joy Township began implementing its Municipal Separate Storm Sewer System (MS4) water quality program in 2018.  Our storm sewer system consists of the Township-owned roads, storm pipes, swales, inlets, and basins that collect and convey rainfall to waterways.  All runoff that passes through the Township’s MS4 and exits through an outfall like the one pictured below is the responsibility of the municipality.

It takes a collective effort to improve the quality of the runoff that ends up in our local creeks and streams.  Rain and snow that does not soak into the ground flows downhill until it reaches a waterway, taking with it any soil, debris, trash, or pollutants.  Remember that the storm pipes and inlets along the roads ultimately flow to surface waters, so help make sure only stormwater flows to the storm sewers!

If you see anything other than stormwater flowing through the storm sewer system, contact Mount Joy Township at 717-367-8917 or email to report it.


Stormwater Management Permits

A permit is typically required for all regulated activities, including:

  • Land development
  • Removal of ground cover, grading, filling, or excavation
  • Construction of new or additional impervious surfaces
  • Construction of structures
  • Installation or modification of stormwater management facilities and conveyances
  • Diversion or piping of any watercourse


Permit applications and instructions can be found on our Forms & Applications page.  Mount Joy Township uses a three-tiered permit system for stormwater management:

Stormwater Exemption – The cumulative installation of 1,000 sf. of impervious coverage on a lot may be exempt from the requirement to submit a Stormwater Management Site Plan.

Small Project – The cumulative installation of 5,000 sf. of impervious coverage and/or earth disturbance may be eligible for approval as a Small Project, which requires volume control for at least the first inch of rainfall from impervious surfaces.

Site Plan – All regulated activities that do not qualify for an Exemption or Small Project must submit an engineered site plan to show stormwater management.

Back to top