Nonpoint Source Pollution

Determining nonpoint source pollution is important in eliminating it. The informative table below lists some sources of pollution, their impact on the environment, and proposed solutions which are useful in conjunction with those outlined in the EHS Storm Water Management Program.

Pollution Sources, Impacts, and Solutions

Pollution Source Impact Solutions

Soaps and detergents to wash vehicles

All detergents destroy the external mucus layers that protect fish from bacteria and parasites. They also lower the water's surface tension, making pesticides and chemicals more easily absorbed by the fish. Some detergents contain phosphates that promote algae growth. When algae decomposes, it uses up the available oxygen of aquatic life.

  • Wash with plain water
  • Use biodegradable soaps and wash over large grassy areas
  • Wash car at a car wash that is connected to sanitary sewer lines

Silt and sediment from construction sites

Sediment collects in drinking water reservoirs, leaving less room for water storage. Sediment and grit also smother bottom dwelling aquatic life, clog fish gills, and block sunlight needed by underwater plants.

  • Innovative and site-specific BMPs
  • Stricter monitoring and education programs

Cleared vegetation, tree trimmings, grass clippings, leaves, and acorns

The debris clogs storm sewers, which increases the risk of flooding. Large collections obstruct water flow and cause creek bank erosion. As this organic matter decomposes, it uses up the oxygen intended for aquatic life survival. Decomposing organic matter also creates foul odors and taste in drinking water.

  • Sweep leaf litter and collect in bags. Recycle matter for compost
  • More frequent street sweeping

Excessive irrigation

Transports fertilizers, pesticides, dirt and grime to local storm sewer or waterway. Fertilizers and pesticides can kill aquatic life. Oil can contaminate drinking water.

  • Fix malfunctioning sprinklers and faucets
  • Water only when necessary and for appropriate amounts of time

Misuse / overuse of fertilizers

Fertilizers contain large amounts of nitrogen and phosphorus - primary nutrients for algae. As it decays, the algae use up the oxygen necessary for aquatic life to survive. Some fertilizers also release ammonia, which is toxic to fish.

  • Limit the amount of fertilizer used.
  • Use of drop spreaders instead of broadcast method
  • The City of Austin Grow Green Program

Misuse / overuse of pesticides

While designed to destroy pests, “broad spectrum” pesticides also poison “good bugs”, birds, and other wildlife. Pesticides also seep into groundwater, contaminate drinking water, and destroy soil by killing essential organisms from microbes to earthworms. Many pesticides are also toxic to humans.

  • Protect storm sewers and areas not needing treatment
  • Substitute with nontoxic products
  • Use sparingly and only as a last resort. Follow the instructions; more is not better
  • Many products are not allowed to be used near or by water drainage areas, follow all instuctions and protect storm sewers and areas not needing treatment

Poorly maintained dumpsters

Liquid wastes can drip out, leach into groundwater, and enter creeks. Un-bagged trash is easily carried to storm sewers and waterways by wind or rain. Open or overfilled dumpsters easily allow wind or rain to carry trash to waterways. Trash and debris clog storm sewers and waterways, which may cause flooding. Dumpsters in poor condition attract flies and rodents whose waste contaminates collected rainwater that cannot be discharged to creek.

  • Get lids to cover dumpsters
  • Build roofs over dumpsters
  • Limit dumpster access to trained personnel

Custodial waste

Mop water, floor wax, cleaning agents, and painting equipment wash water often kill plant life when dispersed on grass. The plant life holds the soil in place preventing erosion. Waste entering storm drain is toxic to aquatic life and can render water unusable for drinking.

  • Restrict use of agents to trained personnel
  • Contain wash water and dispose of properly. Non-hazardous agents may be discharged into sanitary sewer system upon EHS approval


Particularly plastic items that float, spoil the beauty of creeks and lakes and can be harmful to fish and birds that mistake them for food. Litter can also clog storm sever lines increasing the risk of property damage from flooding.

  • More recycling bins
  • Volunteer litter pickups
Back to Top
Back to Top