Article updated by Molly on July 11th, 2022 / Changed the Kuppet disposal to a Walmart link since it's no longer available on Amazon. Also added live pricing via API for both InSinkErator disposals.
Even for those of us who have one, the septic system isn't something we often think about.
But if you own or would like to own a garbage disposal - and you live in a home with a septic tank - it's worth some up-front research.
Because there's some confusion around weather or not it's okay for a septic system and a garbage disposal to coexist in the same home.
In this article, we'll discuss the details surrounding garbage disposals and septic systems, what you need to know about both, and how they can work together.
We'll also show you some of the best garbage disposals for septic systems, based on features like Septic Assist, multi-stage grinding, and increased horsepower/RPM ratings. If you have questions about your garbage disposal and/or septic unit, feel free to leave those in the comments section below and we'll do our best to assist.
If I have a septic system, can I still use a garbage disposal?
Up front, it should be noted that garbage disposals and septic systems can be used in the same house with some important qualifiers. The EPA recommends that you limit the use of a garbage disposal in this scenario to avoid getting too much fat and grease into your septic system.
This means that a garbage disposal should not be used for certain foods that contain a lot of fat, like meat trimmings, bacon grease, or coconut oil.
We'd recommend avoiding putting these in your garbage disposal altogether.
You can read more about what to put down your garbage disposal here.
Avoiding these types of foods is the first step towards making sure your garbage disposal and septic system can work in tandem.
The second thing you can do is get a garbage disposal with multiple grinding stages or simply more power than the average unit.
This will grind up food into smaller bits, making it easier for a septic tank to process.
Best Garbage Disposals for Septic Systems (our top 3 picks)
InSinkErator Evolution with Septic Assist
InSinkErator Evolution Excel (1 HP)
3 grinding stages
Kuppet 1.5 HP Disposal
All three of these disposals have a measure of strength and power that goes beyond the garbage disposals we'd normally recommend.
For septic systems, we'd be looking for one or more of the following features:
- Septic Assist (enzymes designed to help break down food)
- Multiple grinding stages (usually two or three)
- Stronger HP and RPM numbers
While the Septic Assist sounds like the most direct solution, it does have the disadvantage of needing to have the Bio-Charge attachment refilled (or replaced) whenever it runs out. It's also a bit larger than the other InSinkErator models, which will take up a little extra room under your cabinet.
However, it does do an extremely effective job of breaking down food and making it easier on your septic system.
The alternative is simply a more aggressive and more powerful disposal.
This is where the Kuppet and 3-stage InSinkErator come in.
The Kuppet, at 1.5 HP and 3600 RPM, is simply going to overpower whatever you put into it. If you take care to avoid heavy things like bones, as well as fat or grease, the extra power should be enough to all but liquidize food waste.
Let's talk a little more about these three features and why we recommend shopping for them.
1. Insinkerator with Septic Assist
InSinkErator is one of the most trusted garbage disposal brands. They also provide units with a wide range of power and features. Obviously, we recommend this particular model because of that blue, squared-off bottle on the front of the unit. That's a replaceable enzyme Bio-Charge liquid that helps break down the food waste.
Here's a nice graphic that shows how the liquid works in conjunction with the grinding mechanisms:
Otherwise, it's a fairly standard InSinkErator model, with the following notable specs:
- 3/4 HP
- Quieting sound seal
- Easy to install
- 2-stage grinding
So in this model, we get two out of our three requirements. You have the enzymes and the second grinding stage.
For some reason this model does not include a power cord, and it's inconvenient to change the Bio-Charge bottle. Otherwise, it's reasonably priced and probably your best option for a septic-compatible garbage disposal.
2. Insinkerator 3-Stage Grinder
You've got to love the warranty on this model. It's a 7-year "we come to you" deal, which is one of the best we've seen.
It also gets us to 1 HP and three grinding stages, making it one of the more powerful garbage disposals on the market. In keeping with the InSinkErator brand, it also has the Sound-Seal technology, though is far quieter than the Septic Assist model.
Here are a few other noteworthy features:
- Auto reverse with jam sensor
- Listed as safe for septic tanks
- Connection pieces included
While this is a more expensive option, it's easily one of the nicest garbage disposals that InSinkErator makes, especially considering it's both extremely quiet and powerful.
For septic tanks, it wins the day with three grinding stages.
3. Kuppet 1.5 HP Disposal
While Kuppet is a brand that we're admittedly less familiar with, this is one of the most powerful garbage disposals we've seen. At 1.5 HP and 3600 RPM, we'd be comfortable recommending it for septic tank households, especially with the Air Switch.
Remarkably - considering it's power - the unit is also extremely quiet.
At under $100 in most markets, it's also one of the cheapest options we can recommend for septic tank pairing.
So, what features do the best garbage disposals for septic systems have?
The goal is actually quite simple:
For a septic system, your garbage disposal just needs to break the waste down more than what is typical. This is essentially what your stomach does before eventually sending what's "left over" into your septic tank.
This means you need to look for at least one of the following three features.
Enzymes like the ones in the Septic Assist capsules help break down food into smaller and softer pieces. While it can be inconvenient to change these capsules, it's the most effective way to mitigate the risk of having septic-related problems because of your garbage disposal.
#2: Multi-Stage Grinding
Most garbage disposals only have one grinding stage. However, you can get two and even three-stage grinding from some of the more popular garbage disposal brand names. The best garbage disposals for septic systems will have three-stage multi-grind, which will break the food waste down into much smaller pieces.
#3: IncreaseD HP and RPM
All garbage disposals have a horsepower (HP) and rotations per minute (RPM) rating. The typical garbage disposals is rated at 3/4 HP and 1700 RPMs. For septic systems, we'd recommend getting a disposal with at least a 1.5 HP and 3000 RPM rating, assuming you pass on the enzymes and multi-stage grinding.
Things to Always Avoid Pouring Down the Sink
Your septic system, in a sense, has its own ecosystem.
Pouring the wrong substance into that ecosystem can make it difficult for your septic system to function properly and break down waste.
Whether you use a garbage disposal or not, you should avoid putting the following substances down the drain if you have a septic system:
- Hard bones or fibrous vegetables/fruit
- Any kind of paint or chemical compound (even latex-based point)
- Cooking grease, fat, or particularly fatty foods
- Use boiling water to unclog drains instead of solvent
How often can I use a garbage disposal with a septic system?
If you go with one of the units we've recommended in this roundup, it should be okay to use daily, assuming you avoid heavy food waste items like bones and the fatty substances we've already mentioned.
On the other hand, if you have a garbage disposal without septic assist that isn't particularly powerful or does not have a multi-stage grinding system, it would be advisable to use the unit less frequently, perhaps only every other day and only for softer food items.
Dealing with a septic "crisis" is something no homeowner ever wants to go through. At the same time, this doesn't mean you can't enjoy the benefits of garbage disposals like so many other Americans.
The two systems can get along, provided you get the right disposal unit and apply the proper care.
We recommend picking from one of three disposals in the above list.
If you go a different route, prioritize the following features will help make sure you get one of the best garbage disposals for septic systems:
- Enzymes (like Septic Assist)
- Multi-stage grinding
- HP of 1 or higher
Once you have your disposal in place, make sure you take care to avoid using it for foods that are really greasy or high in fat. If you do that, it shouldn't cause you any problems.