Denver's water is about as close to a genuine blank slate as municipal brewing water gets on this site — every major mineral reading sits in the single digits, sourced from Rocky Mountain snowmelt and runoff that simply hasn't picked up much dissolved mineral content by the time it reaches the tap. That makes it one of the least "opinionated" water sources covered here: it isn't pushing a brewer toward any particular style the way a mineral-heavy historic water source would.
Numbers that rival Pilsen's for sheer softness
The figures for Denver's water: calcium 4 ppm, magnesium 1 ppm, sodium 1 ppm, sulfate 4 ppm, chloride 3 ppm, bicarbonate 8 ppm. That's genuinely comparable in softness to Pilsen's historic water profile, the water that made pale, delicately-hopped Pilsner-style lager possible in the first place — though Denver's softness is a modern municipal-supply fact rather than a historic brewing-tradition origin story the way Pilsen's is. A brewer starting from water this soft has enormous flexibility, since there's essentially no existing mineral character to correct for or work around before building toward any target profile.
Colorado's modern brewing scene, built on flexible water
Denver and the wider Colorado Front Range developed into one of the most significant modern American craft-brewing regions, home to a large number of breweries across a wide range of styles rather than one dominant regional specialty — a genuine contrast to the historic European cities on this site, where one style typically came to define the local water's brewing legacy. Water this soft and unopinionated is part of what makes that broad stylistic range practical: no single style is fighting against the base water chemistry, so brewers can build toward pale lager, hoppy IPA, or a malt-forward dark beer with comparable ease.
Using this profile
Because there's so little already present in this water, building any specific target profile with brewing salts is straightforward and predictable — gypsum and calcium chloride additions land close to their expected effect without an existing mineral background muddying the calculation. This is a current municipal reading rather than a fixed historical reference — municipal water composition drifts over time, so confirm your own tap water directly rather than assuming these figures still hold; PeriodicDeck covers the underlying chemistry of calcium, sulfate, and the other ions a water report lists if you want that background before adjusting your own water.