Is Dishwashing Liquid suitable for grey water and septic systems?Updated a day ago
TL;DR: Dishwashing Liquid is septic-compatible and suits grey water systems when used as directed. It is low in sodium, so it does not disrupt the microbes your treatment system relies on, and it carries no phosphates and no chlorine bleach. pH 6.5, made from readily biodegradable ingredients, made in Australia. That covers rural and regional homes on septic, aerated wastewater treatment systems, caravans, motorhomes and boats.
Is Dishwashing Liquid suitable for grey water and septic systems?
✓ Septic-compatible when used as directed
Dishwashing Liquid is low in sodium, so it does not disrupt the beneficial microbes that break down waste in a septic tank or an AWTS. No phosphates, no chlorine bleach, made from readily biodegradable ingredients, pH 6.5.
That covers tank-and-trench septic systems, aerated wastewater treatment systems and standard household grey water setups.
✓ Rural, regional and on the road
If your home or your vehicle runs on a septic tank, a grey water system or a portable water setup, Dishwashing Liquid is a straightforward choice. Follow your system manufacturer's manual, and treat their approved-product list as the final word.
How should I use it on a septic or grey water system?
✓ Three rules for septic and grey water
Use only as directed. 4 pumps, around 16ml, in a sink of warm water covers an everyday load. More product does not clean better.
Never pour undiluted product directly into a septic tank, a grey water line or an inspection opening.
Avoid excessive use beyond normal cleaning. Overdosing any detergent loads the bacterial balance your system relies on.
Scrape food scraps off plates before washing so fats and solids stay out of the line.
What about garden irrigation and edible plants?
⚠ Three things change the answer on reuse
Suitability for grey water reuse is not only about the product. It depends on your soil type, since clay and sandy soils handle irrigation water differently. It depends on what you are watering, because edible crops carry stricter rules than ornamentals. And it depends on your local council, since requirements vary by state and council area.
✓ Practical steps for the garden
Scrape food scraps off plates before washing so fats and solids stay out of the system. Water a small test area first and watch it over a week before you use the water more broadly. If your setup serves a permanent dwelling rather than the garden alone, check your local rules, because licensed installation is required in some states.
Septic-compatible when used as directed. Low in sodium, no phosphates, no chlorine bleach, pH 6.5, 11 ingredients, made in Australia. GECA certified, Sensitive Choice approved, Dermatest tested, Eczema Association recognised.
Dish Starter Kit · new at Koh?
Includes Dishwashing Liquid plus the Dish Pump. Soak your dishes, then wipe and rinse, no scrubbing needed.
Koh Perks · earn points on every order
Earn points on every purchase, refer a friend, and redeem for discounts on your next order. Find all the ways to save in one place.
Browse all Dishwashing Liquid articles
Last reviewed: September 2026 · Koh Australia