Water testing, simple isn’t it?

Clean water is something we take very much for granted in our modern daily lives, but if you give it some thought, a lot of effort goes in to supplying water in volume, that is fit to drink.

You only have to take the recent mayhem caused when Cryptosporidium was discovered in the north west’s United Utilities water supply which required people to boil their drinking water.

Water is complicated stuff, it does after all support life. Fish absorb oxygen from their surroundings. Work your way down the microscopic scale and you’ll find a whole spectrum of odd and unusual creatures that live out their lives in water.

Water sampling

Some are harmful to us if consumed, which is why our drinking water is treated to make it fit for purpose. That fitness for purpose is of course only up to the point of delivery, usually your tap.

If not stored correctly, water can easily spoil just like milk or perishable food.

In large quantities, it is not always practical to keep water refrigerated (one method to stall the development of harmful bacteria).

Water bowsers offer the next best storage alternative, especially if they are approved drinking water vessels and employ WRAS fittings are pre-treated prior to filling and securely closed to preserve the integrity of the water inside.

Providing these conditions are followed you can store drinking water safely for 48 hours and then you need to test it for its fitness for purpose (drinking).

Since we launched our sister website, H2O on site water services earlier in the year, we’ve become pretty busy testing and reporting on water quality.

As well as bowsers, drinking water is often stored in larger vessels such as tankers or even pillow tanks.

Our standard test encompasses the following: Bacteria, Nitrate, Nitrite, Hydrogen sulphide, Sulphate, Total hardness, Total alkalinity, Total chlorine, free chlorine, Chloride, copper, iron, exact PH level, exact temperature. Coliforms and E coli. Quite a list isn’t it?

We also check fixtures and fittings for damage or potential contamination. Inlets and outlets of vessels containing water to be tested are sanitised prior to the test being taken to reduce to “negligible” the risk of cross contamination.

Testing is specifically colour based, with the colour of the sample compared to the calibrated test sheets, calibrated we hear you ask?

Water testing sample

Imagine you have a sheet of card which has colours of test variants printed on it. You’ve been using it a long time. You’ve left it out in the sun a few times. The sunlight has bleached the page slightly.

The colours of your test sheet are no longer a fair comparison.

So, rather like everything else in the clever world of quality control, comparison sheets are in turn compared against a master sheet (calibrated to national standards) and certified as a true match to a specific colour result. The sheet is known as a “correct colour chart“.

Coliforms and E coli tests are a little more involved. A strict sampling procedure is followed to prevent accidental contamination. Samples are incubated at a constant (calibrated) 35 degrees for 24 hours before the test is conducted.

Portable water testing lab

If the sample (which was yellow) is green or blue, those yukky little Coliforms are present.

Testing for E coli involves viewing the sample under UV light (again a measured wavelength or approximately 365mm) Zero fluorescence means no E coli, blue fluorescence indicates the little varmints be there.

Water contaminating E coli must be chlorinated using a set procedure and measure of chlorine, then neutralised to make the water safe for emptying into a public drain.

That’s environmental care. Putting harmless but non potable water back into a biological environment where it will eventually be treated at the water works, once again to be safely delivered fit for drinking to taps and outlets.

Vessels which contained the contaminated water, must be treated and flushed to ensure the contamination is neutralised before being used for drinking water purposes again.

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