Why does my motorhome smell bad? Well, you’ve come to the right place to find out! If you’re driving along smelling like a heap of silage or a pile of rotten eggs, then we can help you diagnose the problem. No-one wants to be the smelly kid on the block; read on to find out what’s causing the smell and how to fix it.
Why Does My Motorhome Smell Bad?
Identify the Problem
How does your motorhome smell bad?
- Sulphur and rotten eggs
- Toilet smells
- Damp and musty
Where does your motorhome smell bad?
- The fridge
- The garage / external storage bins
- The toilet
- The shower
This is the heading
Diagnose & Fix the Problem
Smells of Sewage
This is likely to be an issue with either your motorhome toilet or your grey waste; grey waste is any liquid waste that is not toilet waste and goes into a holding tank or series of holding tanks underneath your habitation space. Not all motorhomes have sink traps so sometimes the smell can come back up through the plug-hole.
- Grey Waste – If the smell is more general throughout your motorhome, you need to empty your grey waste at a suitable dump point, flush out and clean your grey waste tank. Here’s how; access a hose with good pressure and literally get your arm as far into your waste tank as possible giving the hose a good spray around, whilst keeping the drain open. Close the drain and fill the grey waste tank to around 20% and add some specialist cleaner or detergent before driving along some (hopefully) mountainous and bendy roads to your next destination, so the whole lot sloshes around, before emptying on arrival.
Smells of Sulpher / Rotten Eggs
This is either your grey waste tanks or your leisure batteries.
Check your batteries first; if the smell is located in your garage or wherever your leisure batteries are fitted and they are fizzing You’ll know if they are!) then your battery has ‘boiled’.
Grey waste that has been sitting for a long time in a sealed container will smell strongly of rotten eggs because it has stagnated in the tank. This is often a problem if you’ve been parked up for three or more days and then move off with a full or partially full tank of grey waste water.
- Leisure Batteries – boiling the battery will have discharged sulphuric acid onto the battery and its container, and you must assume the battery and container are both coated so do not touch them. Isolate the batteries in accordance with your motorhome instruction manual. Sadly, your battery has probably had it and will need to be replaced; most leisure batteries only last 3-4 years at most. Once your new battery is installed, keep an eye; further problems may indicate a problem with either the charging regulator if you have one, or your van’s electrical system. If in doubt, get it checked by an expert.
- Grey Waste – if the smell is more general, then you’ll need to flush through and clean out your grey waste tank as described in the ‘sewage’ section here.
Toilet smells are common and worse if the weather is hot. They are caused by both the bodily waste held in the cassette and the area around the toilet not being thoroughly cleaned (motorhome loos, in my experience, need much more cleaning than a household loo because they are in a confined space and do not flush in the same way).
- Empty your cassette and give it a very thorough clean. We suggest filling with very hot water and standing upright before adding a capful of bleach, then leaving for at least 12 hours. Some people swear by using bottles of full-fat Coke but this is not something we have tried, we prefer ours with ice and a slice!
- When this has been done, do the same for the toilet and surrounding areas, making sure to get in all the nooks and crannies. There are lots of cleaners out there…I think any type of detergent will do the trick; it doesn’t need to be fancy, expensive or a ‘special’ motorhome product.
Smells Damp & Musty
This can be a hard one to know the cause of and there are a number of possible scenarios.
Check for any obvious signs of condensation, particularly where there is also lack of circulating air; above a pull down bed or beneath sofa cushions for example. Motorhome condensation is caused by introducing moisture into the warm environment of your motorhome. This could be from wet clothing if you’ve been out in the rain, the natural act of breathing over night combined with body heat or simply boiling the kettle. This moisture becomes trapped in the air and eventually settles inside your motorhome, unless there is circulating air to move it around and take it away. Do you always have steamed up windows? Does your bedding feel very slightly damp at night? Do you have small patches of mould? If so, you have ongoing condensation.Where possible, check for leaking pipes in under-sink areas. This is not always easy as some spaces are not accessible, but check where you can.
A damp smell could also be caused by a leak externally, where water is ingressing into the construction and fabric of the motorhome. It can take years for this to become noticeable, especially if it’s a small leak, which they usually are.
- Condensation – remove any wet clothing or laundry you have drying inside and open as many windows and roof lights as possible to ensure good cross-flow ventilation. Clean any mould with a specialist mould remover and follow the actions in the ‘Preventive Measures’ section below.
- Leaks – if you are a plumber or DIY’er then this is probably an easy fix. If not, you may need to get expert help to repair and leaking pipes.
- Damp – if you have water ingressing, no matter how little, it will damage the interior of your motorhome. This can be a major problem if identified and cost many £1000’s to repair. An expert will be able to use a moisture meter to check if this is the case.
CauseIt is highly likely that this will be caused by a poor electrical connection that’s been overloaded and is cooking the surrounding PVC and plastic. It could also be caused by cheap fuses overheating and melting the surrounding plastic.
- Check the fuses, you may have a box or panel in a number of places so check your motorhome instructions. If you have a melted fuse, remove any 230v power source from the mains, power down your electrical systems in the van, switch off the electrical master switch where your main fuse box is and then remove the offending fuse with plastic fuse removal or electrical pointy nose pliers. If in any doubt about this, seek help from an auto-electrician or other suitably qualified person.
- If the fuses all look ok, the you have a loose connection somewhere; this is where we advise you to find an auto-electrician as any diagnostics will involve removing socket covers and exposing wiring.
Smells of Ammonia
If this smell is isolated to your fridge then you have leaking coolant, which can be corrosive. You can also check for yellow powdery deposits along the piping at the back of the fridge, the presence of which will confirm a leak. Gas fridges are different to electrically powered fridges as they need a small amount of coolant to keep them working correctly.
Otherwise, the smell may well be connected to your toilet as when urine is stale, it breaks down into ammonia.
- Fridge – get a motorhome expert to look at your fridge as the leaking corrosive coolant can damage the fridge and further motorhome parts and fabric if not stopped. It is likely that a new cooling unit will be required.
- Toilet – if you think it’s the toilet, then follow the advice here.
There are a couple of smells which are really hard to describe and could be a number of things;
Decomposing Pests – this can be an issue if you have your van in storage and have a double floor. Mice love places like that to nest. If you do find a body, check your wiring carefully as mice also love to chew through cables.
Air Conditioning – this is a very specific vinegary/fishy/musty type smell and means you unit (both cab and habitation) needs re-gassing. If this is the case you will also notice that the unit is losing effectiveness.
Grey Waste Tanks
- scrape dishes and pans before washing to remove as much residue and food waste as possible.
- if you’re on site, utilise their washing-up facilities.
- try using eco-friendly soaps and liquids manufactured without chemicals.
- use a strainer basket on your plugholes.
- where possible, empty your grey waste tank daily.
- flush through and clean regularly.
- fit a SOG system to your loo, this takes smells away by using fresh air via an electrical ventilation system, no chemicals required!
- The flush system on most motorhome loos will not cover the whole bowl with water unless you run the flush for at least 30 seconds; not the best use of your limited water! Keep a spray bottle of water in the loo and use to to cover the bowl after use…this will dilute any residual urine and stop it breaking does so quickly, which is when it starts to smell.
- clean your loo every day, including all the surrounds.
- clean your cassette inside every time you empty it.
- if you use chemicals, make sure you are adding the correct ones and the right amount.
- some people do not use their toilet to poo in, but I can confirm (after years of working in elderly care) that urine smells way more than poo!
However you manage your leisure batteries, they do have a defined life and will not last forever but there are steps you can take to prolongue their longevity.
We are not experts and this is a complex field so were going to duck out at this stage and suggest you visit this really helpful website where you can find out everything you ever wanted to know about leisure batteries!
Condensation & Damp
Preventing condensation in your motorhome can be tricky, unless you want to stop breathing! There are steps you can take which will help though;
- always have a window or roof light open a crack to allow a trickle of fresh air (unless driving). Where possible, have two open to allow for cross-flow ventilation…the best type!
- hang wet clothing and towels outside or under your awning to dry
- leave wet dogs outside (possibly not a popular suggestion though!).
- if you have an extractor, use it when you cook or boil the kettle. If you don’t have an extractor, open the window as wide as possible.
- open roof lights or windows fully when you shower in your van and leave them open for 30 minutes after you’ve finished.
- turn cushions and mattresses regularly and consider storing them elsewhere if you’re not using your van for a long period of time.
- have an annual damp check done; if there is a problem with water ingress such a check will identify it early. You should approach your insurance company if damp is found, you may be covered (if not for the issue itself, possibly for the cost of rectifying the damage caused).
- do not attempt any external fittings yourself where you are required to make a hole in the exterior of your motorhome. If this leads to water ingress and subsequent damp, you may well not be covered by your insurance.
Are you a motorhome beginner? If you’re a newbie, there’s loads of tips and advice in our HUGE guide for motorhome beginners. From buying a motorhome to planning your first trip, you can find it all here.