Online Water Maps Gallery - Interactive Maps

Presented here is a collection of interactive maps that show various water resources information where the user can search for a specific location, zoom in/out to view a particular location or area of interest, select the desired base map, and select the desired information to view a single-layer (tabbed format) or multiple layers (single frame format) of information.

Note – for full functionality please view these maps from a desktop computer and Google Chrome or Mozilla Firefox are recommended; Internet Explorer 9 or 10 may experience some limitations; Internet Explorer 8 and earlier will experience significant function limitations.

Other than the browser requirements, the interactive map tools require no special software or plugins. Please visit Tips, Sources, Access Use and Constraints for user instructions and important information about the data presented on the maps. 

Water Resources of
Chester County 
[Tabbed Viewer]

Water Resources of Chester County - Tabbed Viewer

This Tabbed Viewer presents water resources information in Chester County through synchronized tabs for each element. The Tabbed Viewer includes 2018 PADEP impaired waters, designated stream uses, FEMA floodplains, and USDA soil units.

Water Resources of
Chester County 
[Web Map]

Water Resources Web Map

This Single Frame Viewer presents water resources information in Chester County and allows the user to select which features to display on the map, such as PADEP impaired waters, designated stream uses, and FEMA floodplains.

MS4 Pollution Reduction 
[Tabbed Viewer]

Stormwater and Pollution Prevention - Tabbed Viewer

This Tabbed Viewer presents four data views on MS4 municipalities, Urbanized Areas, and TMDLs in Chester County.

MS4 Pollution Reduction [Web Map]

Watersheds with TMDLs

This MS4 Pollution Reduction web map presents a information on impairments, urbanized areas, parcels, TMDLs, and other information related to municipal MS4 permits. 

2020 Impaired Waters
View by Pollutant (Cause)
[Web Map]

2018 Impairments by Cause

This mapping tool allows the user to view the 2020 impaired waters by pollutant, Cause, assigned by PADEP. Pollutants can be added or removed by selecting the associated box under the Layers list in the top right corner.

Christina River Basin TMDL Load Reductions 
[Web Map]

Christina Basin TMDLs

Thirty-three (33) subbasins within the Christina River Basin have been identified for reductions in nutrient or sediment loads from their stormwater discharges to meet quantitative targets established by the USEPA and PADEP within the TMDL reports.

Real-time Notification
of Flood Levels

Tow Truck at Flooded Road

Using the CCWRA Flood Tool you can quickly access information for 19 U.S. Geological Survey stream gages in Chester County that provide real-time data via USGS web sites and subscribe to receive text or email notifications regarding real-time stream conditions.

Chester County
Hydrologic Unit Code (HUC)


This Hydrologic Unit Code (HUC) map illustrates the boundaries of and provides information pertaining to 8, 10 and 12-digit HUC watersheds in the Mid-Atlantic region, as well as locally named watersheds within Chester County. 

Background: The hydrologic units are a way of identifying all drainage basins and each unit is assigned a numeric code. The units are arranged or nested within each other into successively smaller units. The USGS oversees this classification system.