Cleaning a contaminated water tank

[StuartO]

We have three times suffered water tank contamination,once chemical (from the tap on a French Aire) and twice with the water developing a drainy smell, so something organic got in, perhaps from a garden hose used to fill the tank. We also live in a hard water area, so I have also needed to tackle descaling, although fortunately of a preventative nature, before any obscructive degree of scaling had accumulated. This has all been with the same MH, a 2006 Hymer B674 which we've had from new.

 

We've always taken care to try to avoid taking on contaminated water throughout our ownership and ever since we picked up chemically contaminated water in France, we've always taken a sample and smelled and tasted it before filling. I failed to do this when we arrived at an English campsite with an empty tank where we were directed by the owner to fill up using his garden hose at the back of the reception building which was also their home; it was a new-looking garden hose so I did as I was told.This was a mistake because I took a shower within an hour of doing this and the water smelled drainy in the shower. This exposure was probably the cause of a spectacular illness I suffered about 48 hours later caused by Norovirus; this spoiled our holiday and we had to head for home as soon as I was well enough to drive, which took another 48 hours.

 

The second spell of drainy-smelling water arose after we set off for a short break in UK, having filled up at home before we left. We came back from abroad about 3 months earlier with about 25% ) of perfectly OK water and failed to empty the tank, as we usaully do. I did empty flush and refill before we set off but something organic had taken hold and by the time we got to the destination the water was smelling as it came out of the tap.

 

After the French chemical contamination we flushed repeatedly but used no water treatment and eventually the chemical smell and taste disappeared. For the two organic contamination episode we did resort to descaling and sanitisation, followed by flushing several times. The first time I used citric acid powder (which is a mild acid, primarily a descaler but is also supposed to clean tanks) and it worked and did no harm to out stainless steel Truma water heater. The second time I did a bit more reading and chose to use bicarbonate of soda (baking powder) which I also bought as a 5kg tub from Amazon.

 

In both cases I found it difficult to find what sort of concentration of the stuff and ended up guessing. In both cases I probably over did it, using three or four mugs of the powder dissolved in warm water, tipped into the tank. With citric acid I was twitched about damaging the stainless steel Truma unit, so I only left the citric acid in the sysem for a few hours, then drained it and flushed it out throughly. The second time, using bicarbonate of soda, I followed the advice on a video on YouTube by the makers of Aqua Roll tanks, to use only bicarb but to leave it in the system for 3 or 4 days. Again I probably overdid the quantity, using three or four mugs of powder (compared with their recommendation of three or four tablespoons for an Aquaroll) but that seemed to work well. I filled the tank to the brim before leaving the solution to do its thing for 3 days and when I drained it there were visible flecks of stuff in the water coming out so something had been dislodged, I had also pumped quite a bit of bicarbonate solution through the boiler and into the waste tank, which ended up 25% full - and this also contained (more and bigger) flecks of black organic material as it was drained away. I flushed and then drained the water tank after draining the bicarb, finally leaving it empty for the two weeks of storage before our next trip starts.

 

So have I done this cleaning out well enough? I will flush again before refilling as we depart and this time I will only use our motorhoming blue food-quality hose for the purposes, rather than our garden hose. Our first couple of nights away is to be on a C&CC Club Site, so I know we will be able to get clean water there is necessary for another flush and refill.

 

I'm now fairly happy that (unless you also need descaling) bi the best choice for a cleaning solution. It's a safe chemical - it's baking powder for goodness sake! But what concentration of citric acid or bicarb is desireable for tank cleaning? I suspect it isn't critical and that going a bit OTT, as I did, probably doesn't matter. But somewhere among out body of contributor I'm hoping there is a professional chemist or bacteriologist who can spell out the ideal approach.

 

[EJB]

Thought you had put diesel in from the title.....even that is solvable but I've forgotten where the link is!

Having never 'cleaned', only flushed, before each trip been lucky to never have a problem. ;-)

[Wasnt Me]

Blimey that sounds awful.

 

We only use the water in our tank for washing, flushing the toilet and washing up.

 

Could you get a separate 5 litre can and use this for water in the future and fill directly from a tap?

[witzend]

Tip in one of these https://tinyurl.com/y4xvsbvs fill tank pump some thru the system top tank up to overfill leave for few hrs drain and flush the system a couple of times or until smell goes.

 

We never drink water from the tap either just as we never drink from the hot tap at home

[paulmold]

http://www.biomagicuk.com/index.html

[Steve H]

I also used citric acid but stopped when I noticed that it had stained the internal surface of the filter housing of the water pump.

I now use Puriclean.

https://www.amazon.co.uk/gp/product/B0018331N6/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

The name suggests that it is in tablet form, but no, it's a powder. I use half of the container in our 100ltr fresh water tank. And no matter what others say it IS chlorine based. Close your eyes having mixed it and you could be stood on the edge if the pool at your local swimming baths.

Maybe the secret lies in how and when its used.

On returning from a trip all I do is drain down the fresh water and boiler tanks, I leave the valves open so that any vehicle movement results in water still remaining in the tank draining out.

I don't treat the tank until the next trip. My routine is:

 

Close valves on tanks.

 

Mix half the container of Puriclean with water in a watering can.

 

Pour in to the fresh water tank.

 

Top up the fresh water tank.

 

Pump the solution through the system to fill the boiler tank and all tap and shower points.

 

Leave in the system for 48 hours.

 

Pump the solution through all taps in to grey water tank.

 

Leave for 24 hours (to clean the grey water tank)

 

Drain the grey water tank.

 

Flush through the entire fresh water system.

 

Refill with fresh water and away you go

 

........take the other half of the Puticlean tub with you for use in an 'emergency'

 

 

 

 

 

[Geeco]

The majority of the time we stay on sites where we can hook directly into the local mains water supply. We do this via a food grade hose and an inline carbon/silver filter. We always use bottled water for drinking and never had any issues. My wife was a microbiologist prior to retirement and she is happy with our method. I suspect the key for us is the top quality filtration. The filter we use is www.besidioterfilters.com.au, a local AU brand but I am sure there are equals in UK. Sorry this is not answering the OP's question but I felt still relevant. Cheers,

[Paul-]

We have a caravan that isn't used enough so I use Puriclean at least a coup[le of times a year and descale with white vinegar once a year.

The black organic matter that you mentioned will be dead algae from the pipe walls and this will eventually clear after a few goes with Puriclean. This is often the cause of taps not working as good as they should as they get restricted by the particle buildup.

 

You can get quite a bit of information from water companies if you type into a search engine "smelly water"

oh and I would never use a fitted garden hose as you don't know what the last person used it for.

Bite the bullet and buy some food safe hose.

[Keithl]

Paul- - 2019-08-27 7:19 AM

 

We have a caravan that isn't used enough so I use Puriclean at least a coup[le of times a year and descale with white vinegar once a year.

The black organic matter that you mentioned will be dead algae from the pipe walls and this will eventually clear after a few goes with Puriclean. This is often the cause of taps not working as good as they should as they get restricted by the particle buildup.

 

You can get quite a bit of information from water companies if you type into a search engine "smelly water"

oh and I would never use a fitted garden hose as you don't know what the last person used it for.

Bite the bullet and buy some food safe hose.

 

Totally agree!

 

If I ever get to a tap with a length of hose attached I ALWAYS disconnect it, run the tap for a minute or so then connect my own hose. If I can't use my own hose then I don't fill the tank, simple really!

 

Keith.

[EJB]

Presumably those who use 'Food Safe Hose' sterilise it after every use?

No, perhaps not!! *-)

[Billggski]

Most cases of food poisoning from contaminated water are from cleaning your teeth, washing salads, or rinsing plates. Even ice in drinks can be risky in some countries.

[Will86]

I never take or use ice.

[Alanb]

We started motorhoming over 28 years ago, but so far our travels in our own MH have been limited to the UK.

 

At home we use our garden hose to fill the tank, BUT we always purge the hose with several times its volume of water before filling the tank. Before a trip we also flush the tank, after which we also purge the boiler and pipework. The tank is drained after each trip.

 

As Keith as stated above we NEVER use an attached hose, but use our rinsed food grade hose, or dedicated rinsed container, not an open topped watering can.

 

We do not use bottled water, or keep a container for drinking. As a precaution, I have sanitised the tank several times with Milton. Once when I used too strong a concentration, we had chlorine flavoured water for weeks afterwards.

 

On our numerous trips to NZ, the supplied filling hose was ordinary green PVC garden hose. We always purged this and used it in preference to any attached hoses, and drained it after use. Attached hoses are very common in NZ. Once in NZ we did take on what with hindsight was overdosed rainwater. Horrible, dumped and refilled at next site.

 

Alan

 

[Paul-]

EJB - 2019-08-27 8:35 AM

 

Presumably those who use 'Food Safe Hose' sterilise it after every use?

No, perhaps not!! *-)

 

The big problem with non food safe is the plasticisers leaching from the hose, not the bacteria.

[StuartO]

The scope of this thread is broadening, which may be no bad thing, but I’d still like to know what concentration of bicarbonate of soda is required to clean a tank effectively. The only quantification I came across was the Aquarol video which specified three tablespoons in an Aquaroll - regardless of which of the two sizes of Aquaroll it was. If the larger size is 40 litres (is it?) than six to eight tablespoons would be about right for a 100 litre motorhome water tank.

 

Anyone got a better figure than those?

[EJB]

Paul- - 2019-08-27 5:17 PM

 

EJB - 2019-08-27 8:35 AM

 

Presumably those who use 'Food Safe Hose' sterilise it after every use?

No, perhaps not!! *-)

 

The big problem with non food safe is the plasticisers leaching from the hose, not the bacteria.

I wonder what happens to the water left in the hose until the next use?

Contact is normally about 2 to 5 seconds (and only about 5% actual contact)....could say a lot more but in this day and age when killing 99% of good and bad bacteria is a fashion I always lose :'( ;-)

[Paul-]

StuartO - 2019-08-27 6:21 PM

 

The scope of this thread is broadening, which may be no bad thing, but I’d still like to know what concentration of bicarbonate of soda is required to clean a tank effectively. The only quantification I came across was the Aquarol video which specified three tablespoons in an Aquaroll - regardless of which of the two sizes of Aquaroll it was. If the larger size is 40 litres (is it?) than six to eight tablespoons would be about right for a 100 litre motorhome water tank.

 

Anyone got a better figure than those?

 

As said earlier use Puriclean, its made for the job and most caravan or camping outlets sell it, as does Halfords.

Its up to you, but I wouldn't use bicarb in my water system when Puriclean is available.

[Don636]

This thread has prompted me to clean our vans system before we head off next week and I had enough Puriclean to do the job. Not quite sure why you would want to use bicarb when there is a specialist product readily available.

I’m not fanatical about the water system but do try to remember to clean it once a year. We never drink the water straight from the tank so I don’t worry too much about using the garden hose to fill the tank once I have run the water through for a while.

[StuartO]

Puriclean is one of the products I have bought and it’s in a small tub and comes with dosing information so I plan to carry it with me as a fall back. But while they provide assurances it’s OK with stainless steel it obviously contains chlorine, so I prefer to use bicarbonate, which doesn’t.

[Paul-]

Puriclean doesn't contain chlorine it contains chlorine dioxide as does drinking water, Chlorine (as in hypochlorite) and Chlorine Dioxide are two different products ;-)

 

Milton contains Sodium Hypochlorite and this is why I wont use it to sterilise my system,

[StuartO]

Paul- - 2019-08-28 8:09 AM

 

Puriclean doesn't contain chlorine it contains chlorine dioxide as does drinking water, Chlorine and Chlorine Dioxide are two different products ;-)

 

Milton contains Chlorine and this is why I wont use it to sterilise my system,

 

It may contain a chlorine compound but it still contains chlorine! Chlorine is an element, chlorine compounds can be chemically active and can release chlorine. I prefer to avoid any risk.

 

[Paul-]

Sorry Stuart I edited my post before I saw yours, however its up to you what you use, theres a lot of information on the web on the differences both from water company perspective and from stainless steel manufactures.

[Derek Uzzell]

StuartO - 2019-08-27 6:21 PM

 

The scope of this thread is broadening, which may be no bad thing, but I’d still like to know what concentration of bicarbonate of soda is required to clean a tank effectively. The only quantification I came across was the Aquarol video which specified three tablespoons in an Aquaroll - regardless of which of the two sizes of Aquaroll it was. If the larger size is 40 litres (is it?) than six to eight tablespoons would be about right for a 100 litre motorhome water tank.

 

Anyone got a better figure than those?

 

This link may be of interest

 

https://vehq.com/sanitize-rv-fresh-water-system-without-bleach/

 

The ‘baking soda’ section reads as follows:

 

How To Sanitize The RV Water System Using Baking Soda

 

Baking soda can also be used for deodorizing and reducing buildup in the water tanks. Although it isn’t very effective on its own for actual sanitization, it can be effective when used in tandem with vinegar. Or you could use it its own to regularly descale and deodorize RV water systems.

 

Follow these steps when using baking soda to clean your system:

 

Prepare a solution of 240 g of baking soda dissolved in 3.8L of water.

Fill the tank and run the system with your taps and showerheads on in order to get the solution running through the system.

Letting the solution sit for a while isn’t necessary, but it can help with the effectiveness.

You can also drive a bit to mix the solution around in the tank and water system.

When flushing, make sure to use clean water and continue flushing until there is no more baking soda in the water.

 

Following these steps will ensure that your fresh water system doesn’t have any excess buildup, odd tastes, or odors when you go to drink from it.

 

[StuartO]

Very helpful Derek, thank you. I wonder how the author came up with using 3.8 litres of water? Perhaps he bought a pack of bicarb containing 240 grammes and worked it backwards. I'll try to remember enough schoolboy chemistry to calculate a concentration level and the amounts for a hymer water tank!

 

Clearly bicarb isn't a powerful sanitizer but it's potentially good enough and it has the advantage of being a very benign chemical, so it can't do any harm.

 

For those who asked, I do use a food quality hose (and now only ever this one) for filling the tank and we do carry a separate water container for drinking - and another one as our emergency supply!

[Don636]

I note that bicarbonate - “Although it isn’t very effective on its own for actual sanitization”. Which rather defeats the point of it being used to keep the tank sanitised does it not?

Whereas Puriclean, which has apparently been “Proven in use world-wide for 3 decades”, specifically states “PURICLEAN CAN BE USED IN ALL WATER SYSTEMS INCLUDING THOSE WITH STAINLESS STEEL BOILERS”. This implies that it will not harm stainless steel boilers. Is there any evidence or suggestion anywhere that this claim is untrue? If there has been any such concern over the last 3 decades surely there would be a record of this?