Well Water in Brighton, Colorado

Adams County · Population ~40,000 · Aquifer: Municipal South Platte + Beebe Draw alluvial wells; Denver Basin + alluvial wells on the rural fringe

Hardness: Hard; manganese and TDS are characteristic of the local alluvial groundwater

Brighton's Municipal Water Is Groundwater

The City of Brighton's supply comes from two separate shallow alluvial aquifer systems — the South Platte and the Beebe Draw — via about a dozen city wells, plus up to 2 million gallons a day of purchased water from Thornton (which supplies surface water). The city treats the South Platte alluvial water with reverse osmosis (selected to address contaminants and taste concerns), and runs a dedicated Greensand Filter Plant to remove manganese from the Beebe Draw water before blending. Brighton runs more than 800 water analyses a month and states its water meets all Safe Drinking Water Act requirements.

The Agricultural Fringe: Nitrates

For the rural wells on the agricultural fringe toward Weld County, nitrate is the headline concern. The shallow South Platte alluvial aquifer here is heavily affected by agricultural fertilizer. A long-term Colorado Department of Agriculture / Central Colorado Water Conservancy District monitoring network in adjacent Weld County found that about 70 percent of both monitoring-well and irrigation-well samples exceed the 10 ppm drinking-water standard for nitrate — in 2006, roughly 80 percent of irrigation wells and 70 percent of monitoring wells were above the standard, with irrigation wells averaging around 19 ppm.

Those figures are for irrigation and monitoring wells in the agricultural alluvial aquifer, not a sample of private domestic drinking wells — but they directly document the nitrate load in the exact aquifer underlying the Brighton-to-Weld rural fringe. If you're on a well in this area, nitrate should be at the top of your test list, especially if there is farming or livestock nearby.

PFAS in the Municipal Supply

Brighton's own PFAS information page reports that 2020–2021 testing detected PFOA, PFOS, GenX, and PFBS at levels above the EPA maximum contaminant levels of 4 ppt (PFOA/PFOS) and 10 ppt (PFHxS, PFNA, GenX). The city is not in violation because it is operating under the federal rule's phase-in schedule. Brighton cites aquifers affected by landfills, firefighting foam, and industrial runoff, plus purchased supplies, as the sources. A carbon-filtration upgrade to remove PFAS broke ground in July 2022, targeting completion around 2027 (ahead of the 2029 federal mandate), and residents can obtain temporary filter pitchers in the meantime.

Other Well-Water Concerns

Manganese is characteristic enough in the Beebe Draw alluvial groundwater that the city built a plant specifically to remove it. For deeper Denver Basin bedrock wells on the fringe, the USGS Denver Basin study (SIR 2014-5051, 2003–05) found that bedrock groundwater exceeded secondary standards for total dissolved solids, sulfate, manganese, and iron in roughly 10–20 percent of samples, with TDS rising with depth. Arsenic, uranium, and selenium exceedances were rare in the bedrock (1 percent or fewer of samples) and, in that study, were concentrated in the shallow southern basin near the Palmer Divide — not specifically the northern Adams and Weld area.

Denver Basin bedrock water levels are declining basin-wide (USGS 2015–2023 medians range from about 0.2 to 0.7 feet per year across the aquifers), a relevant consideration for deeper fringe wells. Radon is a Front Range bedrock characteristic worth testing in bedrock wells.

What Brighton Residents Should Know

If you're on City of Brighton water: your water meets all current standards; the active issue is PFAS, which the city is addressing with a carbon-filtration plant (filter pitchers are available meanwhile).

If you're on a private well on the agricultural fringe: test first for nitrate (the documented local problem), plus bacteria, manganese, hardness, and TDS — and, for deeper Denver Basin bedrock wells, radon and arsenic. See our testing guide.