ML3 True Effluent Filters


It has been fifty years since Bob Zabel was issued a United States Patent for an effluent filter for use in septic systems.  Since that time, and especially in the last twelve years, other products have been introduced that are variations of the initial Zabel filter.


All of these had something in common: each incorporated a simple screen to keep solids larger than a certain nominal diameter, typically either 1/16-inch or 1/8-inch, from passing out of the septic tank and out to the drain field.


Some specialty filters followed, designed to retain even smaller-sized solids, from 1/32-inch down to 1/64-inch.  However, most of these filters were maintenance intensive due to their single-screen design.


With the introduction of the new ML3 filter series, Bear Onsite, LLC, brings the first true filter to the industry.  The ML3 filter


provides multiple levels of filtration within the cartridge to allow for progressive removal of smaller and smaller solids from septic tank effluent.  By spreading the removal of solids over several levels, ML3 filters feature a longer service life, while still ensuring that the drain field is protected from excessive solids.   In addition, ML3 improvements aren’t restricted to the cartridge itself, but extend to the filter case, with a design that includes a built-in baffling system to keep solids out of the case, and a settling chamber to slow the velocity of effluent entering the filter cartridge.  This patent-applied-for design allows solids to drop out of the effluent before ever coming into contact with the filter cartridge—therefore, increasing the service life of the filter. 


Finally:  today’s new, true filter design, competitively priced with the screens of the past!


Find a local distributor


Learn more:


Filter Function Brochure                   Filter Applications Brochure


Product warranty information           Product Installation & Maintenance Instructions


State Approvals:























New Mexico


New York


North Carolina


North Dakota






South Carolina


South Dakota








West Virginia



State approvals shown in green

click on state name to view approval


States shown in tan do not issue approvals but have no objection to use of ML3 True Effluent filters. 




877-MLFILTERS (653-4583)     PO Box 507     Somerville, TN 38068     



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