Advice on water treatment please

My local water supply is hardness as calcium 109, pH = 7.44, nitrate 16.3 micrograms per litre, phosphorus 1150 microgrammes per litre, fluoride 0.261 milligrams per litre, sodium 36.2 milligrams per litre.

How should i adjust this for an english style all grain 4% bitter style beer, please ?

What are your magnesium, sulfate and bicarbonate levels? (and is 109 your calcium in ppm or in "as caco3")

Regret that is all the information the water company publish. Hardness is as calcium, and is 109 milligrams per litre.

Well without the bicarbonate numbers you can't calculate residual alkalinity, so no idea what PH you'll get out of the mash.

With limited information I'd either #1 just use your water and buy some five star 5.2 stabilizer (Which buffers your mash PH to 5.2 where it should be)
Or #2 Buy spring water from the store and use that (I'd still get the 5.2 stabilizer)

My water has a high residual alkalinity (Think Dublin) so stouts go well for me. If you have high calcium but enough bicarbonates to even it out you could do nice pale ales (Burton on trent). Most people don't bother to much with water profiling, but if you are at one of the extremes then certain styles will turn out better for you than others.

+1 on the 5.2 Stabilizer. I found that I have a pretty high pH in my Well Water, but it is very soft. I used the 5.2 Stablizer for the first time last weekend and my mash pH was right were it needed to be. I also use Gypsum to increase the hardness of my water.

"The more you overthink the plumbing, the easier it is to stop up the drain."
-Montgomery Scott

It appears that your tap water is not too hard, with an acceptable pH. Your water results are probably listing total calcium as ppm. Your water is fairly soft with a neutral pH, similar to mine. I use absolutely no water treatment whatsoever, except a splash of chlorine/chloramine removers.

Don't stress about you water; it's fine. If you'd like to add the pH stabilizer, great. I'd concentrate more efforts on getting a good grind for your grain, hitting your mash temps, and conducting the sparge that gets you the best results.