Backflow Prevention Device (BPD)


A properly installed Backflow Prevention Device (BPD) is designed to prevent sewage from entering your residence.

If a blockage occurs in the sanitary sewer system, sewage will rise through a manhole and overflow to the surrounding area. However, if your house plumbing is below the level of the overflowing manhole, the sewage can backup through your house side sewer lateral and enter your home through your plumbing drains.

By simply installing a BPD outside the home below the lowest level of plumbing, the overflow will occur outside and avoid damaging the floors and furnishings in your home.

Image above left - a Type-1 BPD, aka "mushroom".  Above right - a Type-1 BPD that has prevented sewage from backing up into a home or business (the residue on the ground is toilet tissue and raw sewage).


BPD's operate automatically and can be reasonably simple to install. Installation may be done by the home owner or by a licensed contractor registered with the District.  A sewer permit is required regardless of whom does the work.


Image above left - a Type-2 BPD (This is typically hidden underground inside a concrete box marked "SEWER".  Above right - a Type-2 BPD that has prevented sewage from backing up into a home or business (the residue on the ground is toilet tissue and raw sewage).  This is typically contained inside a concrete box.


If you are unsure whether you already have a BPD or feel your home may be vulnerable to a sewage backup, contact the District office and schedule a free BPD inspection for your home.


Section 3A of Division 9 of Regulation No. 23 of the Stege Sanitary District:

  1. All new building side sewers including side sewer replacements shall be equipped with a cleanout riser fitted with a backflow prevention device of type and materials as approved by the District.
  2. Where existing buildings have plumbing drain outlets at an elevation that is twelve (12) inches or less above the ground surface of the next upstream manhole or lamphole on the main sewer, the property owner shall have and maintain in an operable condition a backflow prevention device on the building side sewer at the location and of the type and materials as approved by the District
  3. The responsibility for the operation and maintenance of the building side sewer and its appurtenant fittings and devices from the building foundation to and including the connection to the main is the property owner's.”

Standard Details

Backflow Protection/Overflow System - Type 1 or 2 shall be installed in sewers where the lowest drain outlet to be connected to the main sewer is below a point 12-inches above the surface of the nearest upstream sewer structure and in all new buildings.

Backwater Check Valve And Shutoff System - Type 3 shall be installed in sewer serving buildings where a backflow protection/overflow system is required and where sewage cannot overflow to an adjacent area witout serious damage.