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Practical Advice for Dealing with French Drainage

A guide to French drainage by Jenny Bowman from Brittany Architectural Services.

If it’s not been through your body, I don’t want it in my system! The sign that should be on the back of every toilet door of a house with a private waste treatment system.

It’s not a subject that we British like to talk about or usually know anything about for that matter. After all, living in even the smallest English village, our waste is often dealt with by the local council. We never have to fill our heads with how to tackle waste management issues! In France, however, it’s a whole different story. Frankly my knee jerk advice to anyone purchasing a house in France that’s not on main drains would be to get yourself a set of drain rods, quick smart, you never know when they might come in handy! Seriously though finding out more about the type of waste disposal system your new French home has is a must, even before your purchase goes through, as it can very easily turn from dream house to stink hole if not properly addressed.

So, to try and help you to tackle the potential waste issues awaiting you in your new French property and equip you with some basic knowledge of waste management in France, I’ve tried to come up with this short, yet concise guide:

First things first, your estate agent or immobilier should always inform you if the existing waste system of the property conforms to ‘aux norms’ standards, it is part of the sales process. If it does not, then you will be obliged within twelve months of purchase to bring your system up to scratch. If the latter is the case, then you will need to get an ‘etude du sol’ completed. There are companies who can carry out this for you and your agent may be able to recommend one.

Following the etude du sol it is time to think about how you want to update your waste management system. There are a number of ways that the waste your house generates can be dealt with, the main ones being: A traditional system with tank and filtration system, or alternatively you can opt for a more modern Mini Treatment Station. This is the part many of us find overwhelming and often confusing, but don’t worry, it’s really not that complicated and above all DON’T PANIC!

I suggest you do take some time to do a bit of ‘homework’ about fosse septique or as we know them septic tanks, there are over 150 Mini Treatment Stations available licensed for use in France (which is the overwhelming bit!). Depending on what you will be using your French property for, i.e. Holiday home / holiday rental or permanent residence there are different septic tanks that cater to these different needs. It is important to remember though, that units which are suitable for holiday homes are, in general, also suitable for a permanent residence, whereas the inverse is not the case and the waste systems specifically designed for permanent homes should never be used for holiday homes. “Why!? I hear you cry as you find you’ve reached the confusing bit. Well, don’t worry, the reasons are simple. Rural France in particular (where mains drainage seems still to be a thing of the future) is known for having an unreliable supply of constant electricity, in other words expect occasional power cuts. For this reason, waste treatment systems that are licensed for holiday homes are designed to work without power. Even if there is an electric powered pump to carry the clean water to a small infiltration bed in your garden, when the unit is not in use the pump will remain inactive. This means that if you are not at the property you can switch off the electricity before you leave, and the waste treatment system will continue to work peacefully until your return.

So, homework done, and new system installed, the only things now to remember are obviously making sure that the system is regularly maintained and emptied when needed, plus (and possibly the most important thing) be aware of what you put into it i.e. What you’re flushing down your loo as this can have a great effect on the overall efficiency and ‘wellbeing’ of your septic tank. Treat it with respect and it will literally sort out the crap in your life without complaint! A quick list of culprits that will have you knee deep in no time include; nappies, cotton wool buds, cotton cleansing pads; sanitary products; thick tissue etc. In fact, anything that isn’t toilet paper, think twice about putting it down there!

The most pertinent advice that I can really offer to anyone buying a rural French property though, is to ask an expert, get someone out to look at what exists and follow their advice on how to remedy any issues, and always use a fully registered and insured installer!

For free advice on an etude du sol and other drainage matters contact Jenny Bowman at

Photos provided by: Chris Godson at Godson Travaux Public and Stuart & Lindsay Nicholls at Cesar Constructions.


etude du sol = Soil test – required to determine what soil type you have and therefore determining which system is right for your home.