Marseille Soap – The Septic-Safe Choice for a Clean, Green Home

We often get asked if our products are safe to use with a sceptic tank. Specifically our Black Liquid Soap (savon noir) multi-purpose cleaner and the laundry soap flakes. 

If you live with an on-site septic tank, you’ll know how important it is to choose your household cleaning products wisely. Harsh chemicals can upset the delicate balance of beneficial bacteria inside your system, leading to clogs, bad smells, and costly repairs.

That’s why more and more homeowners are switching to natural, biodegradable products – and at French Soaps UK, we believe that traditional Marseille Soap is one of the best septic-safe cleaning solutions you can buy.

Your septic system relies on naturally occurring bacteria to break down organic waste. When toxic substances like bleach, ammonia, or chemical drain cleaners are introduced, these bacteria can be killed off – leaving your system unable to function properly.

This can cause:

• Clogged pipes and drains

• Persistent bad odours

• Overflow and drainage problems

• Expensive repair bills

While there’s no official UK certification for “Septic Safe” cleaning products, environmental agencies recommend choosing 100% natural, biodegradable products with minimal ingredients.

If you’re on a septic system, it’s best to avoid:

• Chlorine bleach and harsh disinfectants

• Ammonia-based cleaners

• Drain unblockers with caustic soda

• Floor waxes and carpet shampoos

• Pool or spa maintenance chemicals

• Cooking fats, oils, and large amounts of body oils

• Medications or bulk chemical cleaners

These can either kill beneficial bacteria or cause blockages in your system.

Instead of chlorine-based cleaners, you can choose:

• Active oxygen bleaches

• Bicarbonate of soda and vinegar for drains

• Traditional Marseille Soap for surfaces, laundry, and general cleaning

Authentic Marseille Soap has been made in Provence, France, for over 600 years using time-honoured methods. Traditionally crafted from olive oil, with no synthetic fragrances, colourants, or added glycerin, it is:

• 100% natural and biodegradable

• Gentle yet effective for cleaning all around the home

• Long-lasting and economical

• Kind to skin and sensitive environments

Because it contains no harsh chemicals, Marseille Soap is completely safe for septic tanks – it cleans beautifully without upsetting the system’s balance.

• Laundry – Grate the soap to make your own natural washing powder

• Surfaces – Lather with warm water for kitchen and bathroom cleaning

• Stain Removal – Rub directly onto fabrics before washing

• Floors – Dissolve in hot water for a natural mopping solution

• Garden Tools – Clean without contaminating soil or water

Even with safe cleaners, you should:

• Avoid flushing non-biodegradable items

• Spread laundry loads across the week to prevent water overload

• Have your septic tank emptied regularly

• Keep an eye (and nose!) out for early signs of trouble

Choosing Marseille Soap isn’t just better for your septic system – it’s also better for the planet. Our bars are plastic-free, last for months, and are made using a slow, energy-efficient process in Provence.

Shop Our Range of Authentic Marseille Soaps

At French Soaps UK, we stock a beautiful collection of eco-friendly, septic-safe Marseille Soaps direct from the oldest soap makers in Marseille. Perfect for your home, your skin, and your septic tank.