The ‘hard’ truth about soft water

Before purchasing a water softener for your home, get the facts on Denver’s water hardness, or lack thereof.

July 27, 2017 | By: Travis Thompson
The South Platte River, pictured here, is part of Denver Water's southern collection system and provides moderately hard water.
The South Platte River is part of Denver Water’s southern collection system and provides moderately hard water.

On the surface, it’s an easy sell.

If you don’t like spots on cleaned dishes, have challenges rinsing off soap in the bath and live in an area with “hard water” — get a water softener.

But, while Colorado may be considered by some as a state that has hard water (according to this U.S. Geological Survey map), for Denver Water customers, the surface is the very reason they should rethink buying into this pitch to soften the water in their home.

That’s because Denver’s water comes from snowmelt and is fed by mountain rivers and streams, also known as surface water. The USGS Water Science School explains that it’s actually the water systems relying on groundwater that have greater water hardness issues since small amounts of naturally occurring minerals dissolve into the water as it moves through the soil and rock.

“The hardness of our water varies during the year,” said Steve Price, water treatment engineer for Denver Water. “Denver’s water is slightly harder in the winter when our waterways and reservoirs freeze, allowing the water to absorb more minerals. It’s softer during late spring through fall when the runoff filters out some of the minerals as the water makes its way into our reservoirs.”

The USGS classifies soft water as anything under 60 milligrams per liter of calcium carbonate. Hard water is identified in the range of 121 to 180 mg/L. There are no health concerns associated with calcium carbonate levels, but hard water can be a household nuisance and leave a chalky or mineral aftertaste.

Denver Water uses two main collection systems for its supply. The southern collection system, which is considered moderately hard with a range of 75 to 120 mg/L, and the softer northern collection system where calcium carbonate levels are typically between 40 and 50 mg/L.

Denver's water is considered to be soft to moderately hard.
Denver’s water is considered to be soft to moderately hard.

“We’re fortunate to have such a pristine water source here in Denver, as our goal is to not only provide safe and reliable drinking water supply, but also one that tastes, smells and looks good,” said Price.

Some people may still choose to invest in a water softener for their home, but Price emphasizes the importance of properly maintaining any in-home device that impacts drinking water.

“Once the water goes through a supplemental water treatment device, we can no longer ensure that it meets Denver Water’s high-quality standards,” he said. “It’s vital that customers properly maintain their water softeners so that they are not unknowingly affecting the safety of their drinking water.”

Despite Denver’s soft to moderately hard water supply, it’s not uncommon to see a sales force for water softening systems in the community.

But buyer beware. In-home water treatment devices have actually been used in elaborate and expensive scams, like the Greeley Tribune exposed earlier this year in its story, “Habitat for Humanity director vows action in wake of ‘misleading’ tactics used to sell Habitat homeowners soft water systems.”

“The bottom line is that when it comes to the safety and integrity of your drinking water, make sure you have all the facts,” Price said. “Contact your utility, research the quality of your water supply and thoroughly investigate any in-home treatment device, water softener or otherwise, before making a purchase.”


Denver Water provides detailed information about water quality from the source to the tap, including annual water quality reports detailing monitoring programs and results, here.

2 thoughts on “The ‘hard’ truth about soft water”

  1. Thanks for the excellent tip.
    I live in a condominium and water is included in my HOA so, I do not get any water bills.
    How do I find out the source of water supply to my home? I would like to know what reservoir or water body is used for pumping water to my residence.
    Also, I plan to get my water tested for nitrates, heavy metals and radioactive elements. Do you recommend any certified labs that I could use?
    Lastly, I wanted to know if the water supply in the kitchen is same as that in the shower or bathroom taps and flush tank?
    Recently, I have seen unprecedented heavy brown sedimentation in my bathroom flush tanks. Not sure if it’s rust or soil.
    I would highly appreciate your response and recommendations to my questions. Any additional suggestions or guidance to healthy water consumption would be of a great value in our life.
    Thank you,

    1. Hey Jay,

      A quick and easy way to see if you’re in Denver Water’s service area is by calling our customer care team at 303-893-2444. They can look up your address and also help you with your additional questions.

      Denver Water serves Denver and most surrounding suburbs. Here is a link with more information and a map:

      If you are in fact a Denver Water customer, our primary water sources are the South Platte River, Blue River, Williams Fork River and Fraser River watersheds. We also use water from the South Boulder Creek, Ralston Creek and Bear Creek watersheds. Because Denver Water has an integrated system, depending upon where you are in our service area and the time of year, you could be getting water from a variety of reservoirs in our system. You can learn more about our collection system and the source of Denver’s water supply, here:

      Denver Water collects more than 35,000 samples and conducts nearly 70,000 water quality tests a year to ensure the drinking water we deliver to your service line meets or exceeds federal and state requirements. Once the water reaches your service line, which is the pipe that connects your residence to Denver Water’s system, the quality of your water is dependent on the type of plumbing you have or any in-home devices – like a hot water heater – that the water touches before going through your tap.

      For details on Denver’s water quality from its collection and storage to the water delivered to your home, you can view water quality reports for the last decade:

      To identify potential causes for discolored water along with steps you can take to deal with a temporary problem, check out this link:

      If you are looking to have the water in your home tested, start with the Colorado Department of Public Health & Environment. Here’s more information on their water testing:

      Hope this helps!

Post a Comment

Your email address will not be published. Required fields are marked *