Wide range of values in water report

In my water report, attached, there is a relatively wide range of values across samples. For example, in one sample hardness is 52 mg/L but in another it's 98. Other key minerals show similar variability (as expected this is correlated, i.e. if one mineral is present in higher concentrations, all of them are - though there is never any chloride or sulfate detected). These wells are all merged together into my water supply. What's the best way to handle this: should I average all the results, or take one or the other extreme? Any other comments on my water? I haven't done a full analysis yet, but am I correct in thinking that my water is ranges from moderately soft to neutral? I started analyzing it because I wasn't happy with the quality of bitterness I was getting and because I'm getting poor mash efficiency (though I suspect that's due to bad MLT design).

View attachment 2007 IOC.pdf

The surest, easiest and safest thing to do is throw your water away by which I mean run it through a reverse osmosis unit which is really throwing away all (or almost all) the minerals in it. This is not really what you want to do (you will have to replace them) but in throwing away the minerals you are throwing away the variation in their levels too. The Primer has tips on how to get started using this approach.

The alternative is to measure hardness and alkalinity (the two easiest to test) of the water at each brew session in order to know what you are faced with on a particular day. Depending on what you determine in this regard you then treat your water accordingly.

If you are lucky and the variances are small (e.g. min hardness 52, max hardness 98, average hardness 75 with standard deviation 5) then you can just work with the averages most of the time and refrain from brewing on the rare occasions when the mineral content deviates from the mean. Or, if you can nail down a relationship between the chemistry and the season of the year (e.g. soft and low alkalinity in the spring at time of snow melt off) you can tune your water treatment for the time of year. Any of these latter approaches will require that you get more information from your supplier about seasonal variations, standard deviations... It's much easier to just use RO and forget about it but you won't learn much about water chemistry using that approach. Of course making good beer may be higher on your list of priorities than learning about water chemistry.

The differences aren't over time - they're from the same time but different wells that all feed into our water system. So the water coming out of my tap is a blend of all the values. According to the water department the values for each well are stable over time.

I'd rather not use RO water, because of the expense and because it feels like giving up - I'd much rather tackle this challenge head on. I feel totally comfortable measuring the hardness and alkalinity at each brew session and adjusting accordingly, though obviously i'd prefer not to have to do that. How do you do a home measurement of those anyway?

Test kits are sold by several manufacturers that use various methods. In general 'drop count titration' in which a sample of the water is measured into a test jar, an indicator chemical added and then another chemical is added one drop at a time until a color change takes place are the most common. Each drop of the added titrant counts for some number of ppm of the parameter being measured. For example, if it takes 5 drops of EDTA to turn a hardness test from red to blue and each drop is worth 10 ppm then the hardness is 50 ppm.