How to read a water report

[Agentgonzo]

I've seen a few posts recently about getting your water profile. The best way is to get your individual water tested or get a test kit and get a report, but as a fallback you can just use your water provider's report. Reading (or even finding) the water report isn't easy and given I went through this about a year ago and other people have asked, so here's (hopefully) a guide to finding and reading your local water report. In the UK, I think that water companies are required to provide water reports (but I don't think the law says what it is required to contain).

Find your local water supplier​

This should be easy. It's the people who send you bills and you pay. For me, this is Bournemouth Water.

Find the latest water report from your supplier​

This is normally a case of googling for "<your water supplier> water report".
For Bournemouth water, this takes you here. Most water companies have some kind of search where you can enter your postcode and get a water report.
If you enter your postcode, you normally get a summary and a link to a detailed water report. Your water company will vary, but the general concepts are the same.
The summary page sometimes gives you high level information, like pH and maybe a hardness level. The rest is probably in the full water report.
This is what I get:

The useful information on here is the Total Hardness level and where to download the PDF.
Go ahead and download the PDF.

Finding the values you need​

Open up your brewing software/water calculator. Most of them require 6/7 pieces of information. If you are only asked for pH, GH and KH values, then see if there is an advanced mode (eg, Grainfather).
The values you probably need to enter are:

1. pH. This should be obvious. I won't try to explain it here
2. CA2+ : Calcium (not hardness or CaCO3)
3. Mg2+ : Magnesium (not manganese)
4. SO4 : Sulphate (not sulphite)
5. Cl- : Chloride (not chlorine)
6. Na+ : Sodium
7. Alkalinity/Hardness/Bicarbonate. I'll go into this in more detail belowe

All values (except pH) are ppm - parts per million. This is the same (for our purposes) as mg/l

For most of these values, you should be able to look them up on the water report. Go for the 'average' value
From my water report, we have (spread throughout the PDF):

My water report does not show Magnesium. I think I just entered in a rough guess. If anyone has any advice for this value if it is not in the water reports, then please let me know and I'll update this post.

Alkalinity/Hardness​

This is awkward to calculate, as different water reports show it in a variety of different ways, as does brewing software. It can be defined in any of the following ways:

• Hardness/Alkalinity as CaCO3 (Grainfather)
• Hardness as HCO3- (Brewfather)
• Hardness as Ca

Fortunately, you can transform one value into another one by a simple formula

• To convert from HCO3 to CaCO3, divide the HCO3 value by 1.22 (source)
• To convert from CaCO3 to HCO3, multiply the CaCO3 value by 1.22
• To convert from Ca to CaCO3, multiply the Ca value by 2.5 (source)
• to convert from CaCO3 to Ca, divide the CaCO3 value by 2.5

So my brewing software (Grainfather) wants the value entered in as CaCO3, but my water report has it in Ca:

166.25 * 2.5 = 290.625, so I enter 290.

Calcium​

My water report doesn't give the value of Calcium, but it is in the summary page. To be honest, I don't know why the water report gives "Hardness Total as Ca" as 116.25 and "Total Hardness level of 23mg/l Ca" in the summary page. I have assumed here that the 23mg/l is the value for the Ca+ ion. But to be honest, I'm guessing and any clarification would be great. I can update this guide.

So entering all these values into the Grainfather app, I have (with a guessed value for magnesium ):

The values will vary throughout the year, the water report won't be 100% accurate and a lot of other variables are at play. But your water supply won't change that much over the the ages, and so getting the values from your water report is a pretty good start.

Disclaimer​

I'm not a water expert nor a chemistry expert. I've probably made a bunch of assumptions (especially with the hardness/alkalinity/carbonate section as I don't fully understand it) so if I have made any errors/omissions, then please do tell me and I'll correct it.

Even if some of the above figures are wrong (either by my explanation or the water report being out of date), they get you closer to your actual water on brewday than pure guesswork. Obviously, it won't be as good as a test for your individual water, or using RO water with ion additions, but it's better than nothing and hopefully helps people who are doing very basic water chemistry additions.

 

[Sadfield]

The best way is to get your individual water tested

I disagree and think what you've outlined along with a alkalinity test kit is the better option. A water test is only applicable for the moment the sample is taken, what comes out of the tap could be totally different when the results return. Where as the water report is the result of a greater, ongoing data set.

 

[Hazelwood Brewery]

Yeah, the problem with water reports is that they give you a “mean” figure over a year where in that time the water company might draw the water from more than one source including underground aquifers and surface reservoirs. The water from an aquifer is likely to be very hard and full of minerals, water from a reservoir is soft and pretty low in minerals generally.

You do have to make some assumptions though unless you run your own water quality lab or send a sample to someone running one before each brew (hoping they don’t switch source while your sample is being processed!). I do use my local water report in combination with a couple of Salifert kits for alkalinity and calcium.

 

[trueblue]

Personally I would not trust a water company report as they are too generic taking samples that can be a long distance apart over a time scale of around a year. I used to get their report but noticed their alkalinity and calcium were out compaired to my own tests. So after listening to brewers with better knowledge than me over on Jim's I when for a tailored report from Phoenix analytical and again there were marked differences. A fellow brewer who lives about 6 miles from me had his own test done at the same so we could compare and there were differences with mine even though our supply was from the same reservoir. I now get my water tested once a year and have found only marginal differences also I always test alkalinity and calcium before every brew and think providing they stay fairly consistent I am happy the rest is OK.

 

[Sadfield]

Personally I would not trust a water company report as they are too generic taking samples that can be a long distance apart over a time scale of around a year.

I now get my water tested once a year

Where's the difference here?

The report example above lists the number of tests, in most cases 9-10 times in 12 months. Surely that's more thorough than one independent test a year?

 

[trueblue]

Where's the difference here?

The report example above lists the number of tests, in most cases 9-10 times in 12 months. Surely that's more thorough than one independent test a year?

As I said, the fact there is very little difference in the yearly reports or between my own test ever brew I am happy my water is fairly stable. The tests I do were spot on with the phoenix reports but were different to the mean average of the generic report.

 

[GotOneBrewin]

Yeah, the problem with water reports is that they give you a “mean” figure over a year where in that time the water company might draw the water from more than one source including underground aquifers and surface reservoirs. The water from an aquifer is likely to be very hard and full of minerals, water from a reservoir is soft and pretty low in minerals generally.

You do have to make some assumptions though unless you run your own water quality lab or send a sample to someone running one before each brew (hoping they don’t switch source while your sample is being processed!). I do use my local water report in combination with a couple of Salifert kits for alkalinity and calcium.

Hi H.B., I'm in Maidstone too. If you were a newcomer to water treatment, what would you first add to your tap water for hoppy pales or best bitters?

 

[Hazelwood Brewery]

Hi H.B., I'm in Maidstone too. If you were a newcomer to water treatment, what would you first add to your tap water for hoppy pales or best bitters?

Hi!

If you’re using 100% tap water the first thing you need is 1/2 a crushed campden tablet to deal with any chlorine/chloramine that might otherwise give your beer a medicinal flavour.

For hoppy beers you might add half a teaspoon of gypsum (calcium sulphate).

For a bitter maybe half a teaspoon of calcium chloride.

Gypsum accentuates bitterness and dryness that you’d expect in a hoppy IPA. Calcium chloride accentuates sweet malty flavours suited for bitters.

 

[GotOneBrewin]

Hi!

If you’re using 100% tap water the first thing you need is 1/2 a crushed campden tablet to deal with any chlorine/chloramine that might otherwise give your beer a medicinal flavour.

For hoppy beers you might add half a teaspoon of gypsum (calcium sulphate).

For a bitter maybe half a teaspoon of calcium chloride.

Gypsum accentuates bitterness and dryness that you’d expect in a hoppy IPA. Calcium chloride accentuates sweet malty flavours suited for bitters.

Thanks for your reply