Septic-Safe Disposals
Updated February 20, 2026
Specially designed for homes with septic systems. Feature finer grinding and may include Bio-Shield enzymes to break down waste before entering the septic tank.
Overview
Septic-safe disposals are designed for homes on septic systems rather than municipal sewer. They inject a dose of enzyme-based solution with each use that helps break down food particles in the septic tank. Standard disposals add solid waste to the septic load, which can overwhelm the system and require more frequent pumping. Septic-safe models reduce that impact. InSinkErator Evolution Septic Assist is the most well-known model. Important: even with a septic-safe disposal, you should still be conservative about what goes down the drain.
Pros & Cons
- Septic compatible
- Finer grinding
- Enzyme treatment available
- Premium pricing
- Still adds load to septic
Key Features
- Automatic enzyme injection with each use to aid septic breakdown
- Bio-Charge cartridge lasts approximately 3-6 months depending on usage
- Same grinding performance as standard continuous feed disposals
- Reduces (but does not eliminate) the additional septic load from food waste
- Available in 3/4 HP -- sufficient for most household use
Sizing & Selection
Most septic-safe models are 3/4 HP. Fewer options than standard continuous feed since only a few manufacturers offer the enzyme injection feature. Size your decision based on household use -- 3/4 HP handles most foods for families of 2-4.
Installation
Same installation as standard continuous feed disposals plus: the enzyme cartridge mounts inside or alongside the disposal body. No additional plumbing or electrical needed beyond standard disposal requirements. Cartridge replacement is a snap-in process -- no tools needed.
Maintenance
- Replace the Bio-Charge enzyme cartridge every 3-6 months (-15 per cartridge).
- Follow the same maintenance practices as continuous feed: cold water, ice cubes monthly, no grease.
- Be extra conservative with what goes in -- septic systems handle less volume than municipal sewer.
- Have your septic tank pumped on schedule. The disposal adds load even with enzymes.
- Avoid anti-bacterial soaps and bleach down the disposal drain -- they kill the beneficial bacteria in the septic tank.
Buying Tips
- InSinkErator Evolution Septic Assist is the market leader and the model most septic professionals recommend.
- Factor in ongoing cartridge cost: -15 every 3-6 months, or -40/year.
- Some septic professionals still advise against any disposal on a septic system. Consult your septic service company before installing.
- If your septic system is already stressed or undersized, a disposal (even septic-safe) may push it over the edge. Get a tank assessment first.