Polluted Lakes in Pennsylvania

Zoom in on the dark red labels to view the polluted lakes. Clicking on a lake will show its name, its source and cause of pollution, and some interested parties involved in its TMDL plan.


This map displays the lakes within Pennsylvania that are considered impaired or polluted under Section 503 of the federal Clean Water Act. Pollution can harm the ecosystem of the lake. The effects of pollutants vary depending on the pollutant; for instance, excessive nitrates and phosphates can lead to algae blooms, while sediments can get trapped in the gills of fish. Drinking or sometimes swimming in polluted water can make people sick, as well.

Because of these negative effects, every polluted lake is required to have a TMDL plan. This plan is a solution created by the EPA and enforced by the Pennsylvania DEP. It specifies the maximum amount of a particular pollutant or pollutants that is allowed in that particular body of water every day. This is known as the lake's load. The plan must be agreed upon by stakeholders. These stakeholders represent the public, the people causing the pollution, and other groups such as the DEP. These stakeholders are named in the map's popups. The purpose of the TMDL plan is to make sure the pollution is dealt with by groups that are most responsible for and affected by the pollution.

In addition to the government agencies identified above, the following agencies are referred to by abbreviations in this map:

The table below contains all the different Causes of pollution mentioned in the map popups. The Total column shows how many lakes suffer from that Cause. As a lake can have more than one cause of pollution, the total number of sources is greater than the number of lakes. Nutrients and sediments (referred to in the data as Total Suspended Solids) are the most common sources of impairment.

Cause Total
Low D.O. (disolved oxygen) 2
Mercury 1
Nutrients 8
Organic Enrichment 3
PH (pH, or acidity) 1
Polychlorinated Biphenyls (PCBS) 2
Total Suspended Solids (TSS) 7