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Wastewater Pollution Prevention


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Wastewater Pollution

All our properties are connected to the Boston sewer system. A sewer lateral, also known as a building's sewer, is the waste disposal pipe connecting a home or business to the BWSC sewer main in the street. Sometimes lateral sewer pipes can get blocked and break inside a commercial building or on the property. Sanitary Sewer Overflows (SSOs) are backups in the public sewer, residential or commercial plumbing. SSOs are caused by many things. There can be a discharge, a spill, or release of untreated sewage into the environment or on property and should be reported to BWSC right away.

Potential Effects of Sanitary Sewer Overflows (SSOs)

SSOs can cause environmental and public health problems. SSOs that happen in streets can cause untreated sewage to go into the storm drain system and travel to local waterways. This can pollute surface waters, endanger aquatic life, and interfere with the enjoyment we get from our waterways and beaches. SSOs that happen inside buildings can damage the property and whatever is inside the building. Clean up and repairs could cost property owners high repair bills and be a danger to our health.

What Causes Sanitary Sewer Overflows (SSO)?

  • A blocked or collapsed private sewer lateral
  • Putting Fats, Oils, and Grease ( FOG) down drains that creates blockages in sewer lines or internal plumbing
  • Putting other things down the drain such as baby wipes or rags, that blocks sewer lines or internal plumbing
  • Blockages or breaks in the sewer lines or in the plumbing inside a building
  • Sometimes heavy rainfall, can cause an inflow of stormwater into sewer lines

To report a sanitary sewer overflow (SSO) or sewer backup, call BWSC's 24 Hour Emergency Service Line at 617-989-7000.

If there is a SSO in your home or business:

  • Avoid contact with the overflow
  • Report any SSO to BWSC
  • Use caution while cleaning an overflow or contact a professional
  • cleaning contractor. See Cleanup Procedures after a Sewer Backup for more information.

After the cause of the sanitary sewer overflow (SSO) or sewer backup is fixed, we should remember the most important cleanup steps; air out the environment and save any valuable property. The longer sewage is allowed to stay on or in our property, the bigger chance for health problems to our tenants, merchandise and ourselves.

Building owners may decide to use a professional cleaning service. Search online or in the phone book for "Water Damage," "Fire Restoration," or "Mold Abatement" to find cleaning companies. It is recommended that building owners check the company's references and determine that the company is insured.

Cleanup Procedures after a Sewer Backup
Remove any excess water from the property by using pumps, wet vacs, or by mopping.
  1. Pump excess sewage back into the unobstructed sewer lateral or into a vacuum truck for removal. Do not pump sewage outside or into the catch basins in the street.
  2. Use dehumidifiers and active ventilation when available
  3. Collect and dispose of all contaminated materials.
  4. Discard or clean contaminated furniture and mattresses.
  5. Wash and disinfect affected areas with a solution of one-quarter cup household bleach to one gallon of water.

What Can We Do?

We all can prevent blocked pipes and SSOs. Many things we put down drains and flush down toilets do not belong in our pipes and can cause leaks and breaks in our pipes.

Fats, Oils, and Grease (FOG) in Restaurants and Food Establishments

Cooking fats, oils, and grease that gets washed off cooking appliances and kitchenware can end up causing problems in building drains and BWSC sewers. BWSC's regulations governing the use of sanitary and combined sewers and storm drains require we properly install and maintain grease traps in all restaurants and food establishments in our City. Grease traps need to be cleaned so they work correctly. Let's keep FOG out of pipes!

Grease traps are devices placed on kitchen cleaning appliances such as sinks, woks, and any other drains that collect grease. Properly maintained grease traps help stop unwanted grease build-up in your private building's sewer or a Boston Water and Sewer Commission sewer.

There are two types of grease traps:

Traps located in an establishment near the fixture it serves and large traps in the ground outside of buildings that serve an entire kitchen.

Grease in buildings and BWSC sewers can come from:

  1. Pot Sinks
  2. Rinse Sinks at Dishwashers
    • Garbage disposals should not be installed on these sinks.
  3. Dishwashers:
    • Dishwashers should only have outside traps
    • Dishwashers cannot flow through a point-of-use trap inside a building.
  4. Woks
  5. Floor Drains and Sinks
  6. Automatic Hood Washers

These are only guidelines for cleaning as most traps are designed differently and have a specific way to be cleaned. Talk to the manufacturer for instructions.

  • Grease traps should be cleaned when 25% of the liquid level of the trap is grease or oil, once a month minimum for point-of-use traps, and quarterly for large in-ground grease interceptors.
  • The cover should be removed carefully to avoid damage to the gasket.
  • Scoop off the layer of grease and oil floating on top of the water.
  • Remove any baffles and scrape clean. After cleaning, the baffles can be rinsed off in the sink that flows to the trap.
  • Using a strainer, scrape the bottom of the trap to remove all non-floatable food particles and debris.
  • Clean the bypass vent with a flexible probe or wire.
  • Reinstall baffles and cover.

The grease trap should be completely emptied once a month. Many businesses have an independent contractor that specializes in grease trap cleaning do the work. All interior grease trap installations are subject to state and local plumbing codes.

In food establishments grease and solids that enter a grease trap remain in the trap, separate from the water that gets flushed into the sewer system. Every so often, the trap needs to be opened and the grease and solids removed to make sure the trap continues working properly.

Wipes can cause blockages in the pipes. When they get big enough, clogs often cause pipes to crack, letting water from our sinks and toilets to enter homes and the environment.

All wipes should go into the trash even if they say they're flushable. The only thing that should ever be flushed down a toilet is toilet paper. We can save a lot of money on pipe repair bills and the hassle of broken pipes.

Wipes that should be thrown in the trash, and not flushed down the toilet, include:
  • Bathroom wipes
  • Baby wipes
  • Disinfecting wipes
  • Towelettes
For more information see our Keep Wipes Out of Pipes brochure in English or Spanish.
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  • Boston Water and Sewer Commission
  • 980 Harrison Ave. Boston, MA 02119
  • (617) 989-7000