By SemperScreen®. We own residential and commercial real estate properties across the United States, and we built the permanent sink screen for our own buildings before we sold it to anyone else.
The U.S. Environmental Protection Agency answers this one directly. Its homeowner guide tells septic owners to eliminate or limit the use of a garbage disposal, and it names the replacement in the same breath:
"Eliminate or limit the use of a garbage disposal. Mesh strainers or catchers for the sink drain are cost-effective alternatives." U.S. EPA, A Homeowner's Guide to Septic Systems, September 20251
That is the federal agency responsible for onsite wastewater, telling you to take the disposer out and put a catcher in the drain. The rest of this article is why, what your state code adds, and how the options differ.
Does your county even allow a disposal on septic?
Sometimes not, and where it is allowed, the tank sizing rule usually changes.
This is not a plumbing code question. Plumbing codes govern how a disposer is installed. Whether one may connect to an onsite system, and what tank it needs, lives in your state's onsite-wastewater rules and with your county health department.
Minnesota is explicit: if a garbage disposal unit is anticipated or installed in a dwelling, the septic tank capacity must be at least 50 percent greater than the base requirement and must include either multiple compartments or multiple tanks.2 That is not a recommendation. It is the sizing rule.
Minnesota is not unusual. Most state codes require a septic tank size increase to account for the additional sludge and scum a disposer generates, though the same technical guidance notes those codes generally offer no corresponding advice on increasing drainfield (or leach field) size.3 Cornell's waste management guidance puts it plainly: disposals are not recommended for use with septic systems because they increase the necessity of pumping, and the required minimum tank size increases with one installed.4
What this means in practice. If your tank was sized for your bedroom count without a disposer, and someone later installed one, your system is running above the load it was designed for. That is the common situation, and nobody gets a letter about it.
Before you install or replace one, call your county health department and ask two questions: is a disposer permitted on an onsite system here, and does my existing tank meet the sizing requirement with one connected.
SemperScreen® recommends that you always refer to local building codes when modifying a building's plumbing system.
What a disposal actually does to a septic system
It does not make food disappear. It makes it smaller, and sends it somewhere it has to be removed from by truck.
A septic tank works by time and stillness. Solids settle to the bottom as sludge, oil and grease float to the top as scum, and the clarified liquid in the middle flows out to the drainfield.1 Anything that adds to the sludge and scum layers shortens the interval before those layers reach the outlet.
The EPA is direct about where disposal waste ends up: food waste is slowly digested by the bacteria in the tank and accumulates as scum and sludge, which is why the agency tells homeowners to limit disposer use.5 Its longer homeowner guidance is more pointed still, noting that frequent use significantly increases sludge and scum accumulation and results in the need for more frequent pumping.1
The measured effect is not marginal. Research summarized for the septic industry puts the increase in suspended solids entering the tank at roughly 30 percent, with biological oxygen demand rising by up to 50 percent, and recommends either a 50 percent larger tank or shorter pumping intervals where a disposer is used regularly.6
And it runs in reverse. Eliminating garbage disposal use reduces the rate of sludge and scum accumulation in the tank, which reduces the frequency of required pumping.3
Why this is a drainfield question, not a tank question
The tank is replaceable. The drainfield is the expensive part.
When sludge builds past the point the tank can hold it, solids migrate through the outlet and reach the drainfield, where they clog soil pores. The EPA warns that a tank full of solids may eventually clog the drainfield and require replacing the whole field.7 The septic industry puts drainfield replacement at $5,000 to $15,000.6
Set that against routine maintenance. The EPA's homebuyer guidance puts a typical inspection and pumping service at $250 to $500 based on nationwide industry estimates.8 A disposer does not change the price of a pump-out. It changes how many of them you buy, and it raises the odds of the outcome that is not a pump-out at all.
One more thing not to bother with. Additives that claim to break down sludge and eliminate pumping are not recommended, because the tank already contains the bacteria, enzymes, yeasts and fungi that do that work, and additive products can be ineffective or actively harm the system and the environment.1 Technical guidance for onsite systems adds that additives may interfere with treatment, damage the drainfield, or contaminate groundwater beneath it.3
We already have one. Is taking it out worth it now?
Usually yes, and the honest version of the answer has two halves.
What removing it does. It stops adding to the accumulation rate from the day it comes out.3 If you are on a three-to-five-year pumping cycle and you are shortening it because of disposer load, removing the disposer is what moves you back toward the interval your tank was designed for.
What removing it does not do. It does not undo sludge already in the tank. That comes out at your next pump-out, not before. If you have been running a disposer for years on a tank sized without one, book the pump-out and have the technician tell you the sludge depth. That number, not this article, tells you where you actually stand.
Two situations make removal more urgent rather than less. A tank at the minimum size for your bedroom count with a disposer connected, which is the sizing mismatch described above. And an older system: the EPA advises that if a septic system is more than 25 to 30 years old, you should start planning for an upgrade before you are in an emergency, because it is likely near the end of its useful life.7
If you rent the place out, this gets worse
Guests and tenants do not know they are on septic, and nothing about a kitchen sink tells them.
This is the specific reason rural and lake-country short-term rentals fail here. A guest scrapes a plate into the sink because that is what they do at home. The system is on a three-year cycle nobody is watching, in a property the owner visits between bookings. The failure does not present as a slow drain. It presents as a backup during someone's stay, or as a drainfield you replace two years early.
A removable cover does not solve it. In a rental it is a part that gets lifted out to drain a pot, left on the counter, thrown away with the scraps, or simply not put back, and from that moment the system is unprotected. That is human error that no training program fixes, and a laminated sign in the kitchen does not fix it either.
Note for owners: rentals of any kind, including short-term rentals, take the 5-year commercial warranty rather than the residential one.
What goes in the drain
Something has to. Model plumbing code requires a device restricting the clear opening of a sink waste outlet whether or not a disposer is present, so an empty flange is not an option. We compared the three choices and their costs in what to install after removing a garbage disposal.
For a septic property the choice narrows on one axis: does it stay in the sink when nobody is thinking about it.
The SemperScreen® permanent sink screen is the only non-removable permanent sink screen on the market. It is Type 304 stainless steel with a polished finish and a brushed trim ring, one pound, fitting standard three and a half inch drains with a custom tube nut on the one and a half inch tailpiece for more thread contact. Its proprietary double-walled technology gives it a perforation surface area exceeding that of the connecting pipe, so it is not the narrow point in the drain. It has been tested and COMPLIED with ASME A112.18.2-2020 / CSA B125.2-20, with the detail on our certifications and testing page.
Installation is a retrofit at about fifteen minutes per drain with no plumbing modifications. More than 20,000+ sold since 2017. Owner-occupied homes carry a lifetime residential warranty.
Clearing it is a point-of-use task. Whoever used the sink moves the scraps into the bin with a paper towel or a hand, in a second or two. On a septic property those scraps go to the trash or the compost heap, which is exactly where the EPA's guidance wants them.1
"Works great on our rental units. No more sink issues!" John M, Multifamily Property Owner
Sample kit ships free. No purchase commitment.
If you would rather buy locally or have a plumber fit it, use Find a Store or Plumber. If the scraps are going to a heap rather than the bin, composting food waste is the natural companion to this.
Frequently asked questions
Can you use a garbage disposal with a septic system? In many places yes, but the EPA advises eliminating or limiting use because food waste accumulates as sludge and scum and increases pumping frequency.1,5 Some counties prohibit disposers on onsite systems or require health department approval, and many states require a larger tank when one is installed.2,3
Does a garbage disposal require a bigger septic tank? In several states, yes. Minnesota requires at least 50 percent greater tank capacity plus multiple compartments or tanks where a disposal unit is anticipated or installed.2 Most state codes require some size increase.3 Check your state's onsite-wastewater rules rather than the plumbing code.
How much more often will I need to pump? That depends on tank size, household size and use. The EPA lists disposer use as one of the factors determining pumping frequency alongside tank size, household size and water habits.7 Ask your septic professional to record sludge depth at your next service and use that as your baseline.
Do septic-safe disposals or additives solve this? Additives do not. The tank already contains the organisms that break down solids, and additive products can be ineffective or harm the system and the environment.1 Technical guidance adds they may interfere with treatment or damage the drainfield.3
What is the actual cost of getting this wrong? Routine inspection and pumping runs about $250 to $500 nationally.8 A drainfield clogged by migrating solids runs $5,000 to $15,000 to replace.6 The gap between those two numbers is the reason this article exists.
References
- "A Homeowner's Guide to Septic Systems for Tribal Communities: Do Your Part, Be SepticSmart!" U.S. Environmental Protection Agency. September 2025. Retrieved from https://www.epa.gov/sites/default/files/2015-01/documents/tribal-septicsmart_homeowners_guide_508_v_02_0.pdf
- "7080.1930 Septic Tank Capacity." Minnesota Rules, Office of the Revisor of Statutes. Retrieved from https://www.revisor.mn.gov/rules/7080.1930/
- "Onsite Wastewater Treatment Systems Special Issues Fact Sheet 2: High Organic Strength Wastewaters Including Garbage Grinders." Published by Miami County, Indiana. Retrieved from https://www.miamicountyin.gov/DocumentCenter/View/980/High-Organic-Strength-Wastewaters-Including-Garbage-Grinders-Fact-Sheet-PDF
- "Your Septic System." Cornell Waste Management Institute, Cornell University. Retrieved from https://www.css.cornell.edu/cwmi/waterquality/septic/CCEWQ-YourSepticSystem-Print.pdf
- "How to Care for Your Septic System." U.S. Environmental Protection Agency. Retrieved from https://www.epa.gov/septic/how-care-your-septic-system
- "Garbage Disposal and Septic Systems: Can You Use One Safely?" The Septic Guide. 2026. Retrieved from https://theseptic.guide/guides/garbage-disposal-septic-systems
- "Frequent Questions on Septic Systems." U.S. Environmental Protection Agency. Retrieved from https://www.epa.gov/septic/frequent-questions-septic-systems
- "Homeowner's Guide to Septic Systems: A Homebuyer's Guide." U.S. Environmental Protection Agency. Retrieved from https://www.epa.gov/sites/default/files/2017-08/documents/170803-homebuyerssepticguidebrochurelayout_508c.pdf
