Thornton's 2025 water quality report puts hardness between 152 and 356 mg/L, averaging about 230 mg/L, or 13.5 grains per gallon. Anything over about 180 mg/L is considered very hard.
What hard water costs you
- Water heaters that fill with sediment and fail early
- Tankless heaters that need frequent descaling
- Faucet cartridges, shower valves, and toilet fill valves that stiffen and drip
- White scale on fixtures and glass, and soap that won't lather
Sizing a softener for Thornton water
A softener has to remove the hardness in every gallon your household uses. As an example, a household using 300 gallons a day at 13.5 grains per gallon needs to remove about 4,000 grains a day. An undersized unit regenerates constantly and wastes salt and water; an oversized one costs more than it should. Thornton's hardness also changes through the year, so the settings matter as much as the size. We test at your tap and size the unit to your water and your household.
How we install it
- A bypass valve, so you can take the softener offline without shutting off the house
- A proper drain connection for regeneration
- Outdoor faucets left on hard water, so you're not softening lawn and garden water
- Settings matched to your measured hardness
Already have one?
If scale is coming back, the salt hasn't dropped in weeks, or the control valve is showing an error, the softener may just need a part, a cleaning, or new settings. We'll tell you if that's all it needs. More on softeners →
Hardness for the rest of the metro: How hard is the water in your Denver-area city?
Source: Thornton 2026 water quality report (2025 hardness data). Checked October 2026.
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