What Not to Flush

What Shouldn’t I Flush?

The primary function of the sewer system is to convey human wastes and water. The following products should never be flushed:

  • Fats, Oils and Grease (FOG)
  • Disposable wipes, rags and other rubbish
  • Pharmaceuticals (medications)
  • Household hazardous wastes: paints, solvents, insecticides, herbicides, etc.

Where are these Products Coming From?

Fats, oils, and grease and are usually byproducts of cooking and come from meat, lard, shortening, butter, margarine, food scraps, sauces, and dairy products. Disposable wipes (such as baby and cleaning wipes) and other types of rags and rubbish, pharmaceuticals (prescription and non-prescription medicines), paints, solvents, insecticides and herbicides are all commonly used in the home.

FOG usually enters wastewater when washing pots, pans and dishes because the hot water and detergents liquefy FOG. Cooler temperatures and reduced turbulence in sewer pipes allow liquefied FOG to harden, accumulate and clog sewers.

Wipes, rags and other rubbish don’t break down in the wastewater and might get caught up in the sewer lines. Both FOG and rags may create bottlenecks in the sewers and eventually block them, which can cause sewer overflows and backups. Overflows and backups are messy and unhealthy and thousands of gallons of wastewater may overflow into local waterways or backup into home basements. FOG and rags also cause pump stations to malfunction which might cause sewer overflows and backups.

Flushed pharmaceuticals (both prescription and over-the-counter medications) can get into our lakes, rivers and streams. Recent research indicates that fish and other aquatic wildlife are being adversely affected. Also, long-term exposure to low levels of antibiotics might result in the evolution of drug-resistant microbes and bacteria. However, according to U.S Environmental Protection Agency (EPA) there are no known human health effects from low-level exposures.

Improper disposal of hazardous household products can pollute the environment or injure workers. Wastewater treatment plants are not designed to efficiently handle hazardous substances and it might harm the micro bacteria necessary to adequately treat the wastewater.

When you flush substances down the drain that do not belong there, consumers like yourself ultimately have to pay the extra cost to repair sewers and pumps and to keep the treatment plant working properly, as well as the extra cost of the environmental impacts.

What is UOSA Doing?

UOSA has a dedicated crew that is available 24/7 to deal with sewer overflows. Their daily work tasks include cleaning the sewer pipes and maintaining the pump stations to keep them clean from FOG and other debris. UOSA has also invested in sewage grinders to keep the rags from blocking the sewage pumps. The UOSA water reclamation plant includes several treatment processes that help remove pharmaceuticals. UOSA analyzes its discharge for many chemicals and contaminants – going beyond the imposed Federal and State testing requirements by voluntarily testing its discharge for contaminants that are typically associated with the more stringent drinking water treatment requirements.

As more pharmaceuticals and hazardous wastes enter the water reclamation plant, the cost of running and maintaining the treatment processes increases, and there is no guarantee that all the chemicals will be removed.

What can I do?

There a few easy steps that you can take:

  • Never pour kitchen greases or oils down the drain – even if you think you are washing it down with hot water.
  • Pour cooled grease into a can and throw it in the trash.
  • Scrape grease and food scraps into the trash can.
  • Put baskets/strainers in sinks to catch food scraps. Toss scraps on a compost heap, or into the trash.
  • Pretty much all other solids except for human wastes and toilet tissue should be thrown in the trash can and not in the toilet. Don’t flush wipes, paper towels, facial tissues, paper napkins, wrappers, gloves, condoms, underclothes, elastics, plastic bags, bottles, cotton-tips, cotton balls, tampons, cigarette filters, toys, cans, sticks, pebbles, sand, cat litter, stockings and rags down the toilet.
  • Do not flush pharmaceuticals down the toilet or drain unless the label or accompanying patient information specifically instructs you to do so.
  • Check with your local government if there are any programs that collect drugs at a central location. If no such programs are available, pharmaceuticals may be disposed of in the trash. Please make sure that the materials are securely wrapped to minimize tampering.
  • Household hazardous waste should be brought to a local household hazardous waste collection site. Fairfax and Prince William Counties and the cities of Manassas and Manassas Park have hazardous waste collection sites, free of charge for their residents. For further information look at the links provided below.


Don’t treat toilets and drains as trash cans!

Where can I get More Information?

Fairfax County:

Prince William County:

Manassas City:

City of Manassas Park:

General information: