Nitrate removal from potable water

[Dave Baker]

I've just bought a house in Scotland with its own well and the nitrate level is 70 ppm, above the 50 ppm approved level. Anyone have suggestions for systems to make the supply legal?

[GB]

Google turns up this

[The Natural Philosopher]

I think you mean mg/litre not ppm

And basically, you dont have to do anything to make it legal, because it already is - in england anyway

"For levels of nitrate above the standard but below 100 mg/l and no likelihood of water consumption by resident infants, there is no requirement to serve a Regulation notice but there is a requirement to give advice to owner/occupiers that warns them of the need to prevent the water from being used by any visitors for bottle feeding of infants. There must be a record held by the local authority to show that such advice has been given and received."

basically unless you arer bottle feeding babies its not rgarded as a hazard, merely something you should be aware of.

You CAN if you want buy a reverse osmosis filter for drinking water or fit an ion exchange unit. I haven't pursued the web searching far enough to establish whether or not a standard water softener will do this, but it appears anecdotally that it wont.

Filtering and boiling do nothing, and make things worse, respectively.

I would advise considering the relative costs of

- installing ion exchange for the whole house.

- installing a reverse osmosis purifier for drinking water only.

- buying bottled water for drinking.

- doing nothing at all.

[Robin]

With some caveats - eg if the property is to be used for holiday lets then IIRC it comes within the same limits as commercial properties and ought to be be brought below 50.

[Tim Streater]

Are these different?

[Martin Brown]

At 4C and 1atm they are exactly the same by definition of SI units. Most trace analysis is done at room temperature - technicians prefer it.

ppm is often used for both mg/L and mg/kg in most chemical analysis. The difference is small and in most cases insignificant.

You might also want to check copper and arsenic levels (and uranium) in an old well too. Trace copper in water can be remarkably bad for you.

[GB]

I linked to a reverse osmosis filter for under £200. At that sort of price, why would anyone *not* use one?

[Martin Brown]

The cost of energy to run it and the huge volume of waste water that it produces roughly 20:1 waste to purified water for small systems.

[dennis]

Don't you end up with too much sodium if you use a normal domestic ion exchange softener? That's why you should have a separate drinking water tap.

The reverse osmosis filter sounds best but they can be expensive for large volumes and dirt cheap (

[The Natural Philosopher]

in that the specific gravity of nitrates is not unity, slightly I would think.

[The Natural Philosopher]

£200 buys a lot of bottled water.?

[The Natural Philosopher]

That may not be an issue if the 'waste' water runs the non potable taps and fills the bog cisterns etc.

[The Natural Philosopher]

well unless you are someone who dare not eat a bag of crisps, no.

well yes. legally. Its is bollocks and I often drink softened water here.

[Reentrant]

Also you could mix the RO water 50/50 with fresh well water and still have potable water (35 ppm nitrate). In fact you might prefer to as pure, demineralised water is unpleasantly tasteless.

[The Other Mike]

£200 buys not a lot of bottled water!

[Martin Brown]

Last time I looked Tesco's own brand was about £2 for 5L.

So £200 will buy you 500L or a couple of years worth at UK latitudes allowing for food water content. You might do better in bulk.