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Top 10 Reasons the Effluent Filter Plugged

Sara Hager PhD is an engineer, researcher and instructor in the

Onsite Sewage Treatment Program in the Water Resources

Center at the University of Minnesota. She presents at many

local and national training events regarding the design,

installation, and management of septic systems and

related research.

Ms. Hager is education chair of the Minnesota Onsite Wastewater Association and National Onsite Wastewater Recycling Association

and serves on the National Sanitation Foundation (NSF) International Committee on wastewater treatment systems.


Ms. Hager wrote an article published in Onsite Installer Magazine

on April 16, 2020. "Top 10 Reasons the Effluent Filter Plugged."

She wrote  ”Large volumes of wastewater generated in a short period of time can result in turbulence in the septic tank and reduced retention time, which can lead to solids plugging the effluent screen. Leaks and large parties are examples of such uses.”


She advises contractors to tell homeowners “Not to do all the laundry  in one day. Spread wash loads throughout the week  and wash at

times when there is not a lot of water being used in the home.

Do not run multiple water devices at the same time, such as

showering and/or running the dishwasher while doing the laundry.”

When an effluent filter completely plugs, it creates serious issues

A plugged filter does not allow wastewater to pass through the septic tank into the pump chamber. As a result, wastewater backs up until

it reaches the top of the septic tank.

When the tank is full, the wastewater enters the inlet pump coming

from the house. When it reaches the house, it surfaces in basement

floor drains, toilets, and showers.


The second problem occurs when the plugged filter is pulled out of the septic tank to be cleaned. The backed up wastewater along with scum and sludge floating on top of the water surges through the septic tank outlet into the pump chamber.                                                                   

All the problems created by the effluent filter can be solved

by installing a ClearFlow Pressure Filter

  • A pressure filter is installed on the discharge port of the pump, which means It is not affected by using large amounts of water in a short period of time.

  • It eliminates any possibility of wastewater backing up                    in the septic tank and into the house.

  • It eliminates any possibility of solid waste                          migrating from the pump chamber to                                          the drainfield.

The 3"x18" 316L stainless steel screen provides 1/16" filtration

  • 316L stainless contains molybdenum, an alloy            that increases strength & hardness and                                enhances resistance in corrosive environments. 

  • The screen is 40% open that allows 83 gallons                           per minute at one psi. 

  • Shock waves created when the pump runs                            provides a self-cleaning action. 

  • Even if the screen becomes completely plugged,                          the alarm will sound. The screen can be taken out,              cleaned and put back without any solid debris                        entering the force main. 

  • We recommend having a professional with a                          POWTS Maintainer Registration clean and                          maintain the filter.  

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Septic system illustration.jpg

The excess wastewater in the pump chamber causes the pump to run much longer than normal.

The excess water causes the drainfield to become severely saturated. When the pump stops,

the solid waste that entered the drainfield settles to the bottom of the lateral pipe(s) causing orifices to plug.


Plugged orifices cause permanent uneven wastewater dispersal accelerating biomat buildup.

This situation does not provide any warning until it is too late to do anything about it.

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