Complete Guide to Water Contaminants 2026 – South Dakota & Minnesota | Applied Water Midwest

If you live in Eastern South Dakota or Western Minnesota, understanding what’s in your water is the first step to protecting your family’s health. At Applied Water Midwest, we’ve tested thousands of water samples across the region — from Watertown to Sioux Falls to Aberdeen — and the same issues come up again and again. This guide covers everything you need to know about the most common water contaminants in our region in 2026.

Hard Water — The Most Common Problem in South Dakota

Hard water is the single most widespread water quality issue in South Dakota and Western Minnesota. It’s caused by dissolved calcium and magnesium minerals that accumulate as groundwater passes through limestone and chalk formations.

South Dakota groundwater is among the hardest in the nation. Watertown, Sioux Falls, Aberdeen, and most rural areas see water hardness consistently above 15–25+ grains per gallon — far above the 7 GPG threshold considered “hard.”

Signs You Have Hard Water

• White crusty deposits (scale) on faucets, showerheads, and appliances
• Soap that doesn’t lather well — leaves a filmy residue on skin and hair
• Spots on glasses and dishes after washing
• Reduced water heater efficiency — scale buildup on heating elements
• Shortened appliance lifespan (dishwashers, washing machines, water heaters)
• Stiff, scratchy laundry

Hard water costs the average South Dakota family hundreds of dollars annually in extra soap, detergent, and shortened appliance lifespans. A quality water softener eliminates these problems immediately. See our complete Water Softener Guide 2026.

Chlorine and Disinfection Byproducts

Municipal water utilities add chlorine (or chloramines) to kill bacteria and viruses — this is an important public health practice. However, residual chlorine in tap water affects taste and odor, and can cause skin and eye irritation. Chlorine also reacts with organic matter in water to form disinfection byproducts (DBPs) like trihalomethanes, which have been associated with health concerns in long-term exposure studies.

A carbon filtration system or reverse osmosis system effectively removes chlorine and chloramines. All Applied Water Midwest systems address chlorine removal as a core function.

Lead — A Serious Health Concern

Lead is not naturally present in South Dakota’s water sources — it enters water through aging lead service lines, lead solder in older plumbing (pre-1986), and brass fixtures. Lead at any level is unsafe, especially for children. The EPA action level of 15 ppb is a response threshold, not a safe level — there is no safe level of lead exposure for children.

If your home was built before 1986 or you have older plumbing, testing for lead is especially important. Our free water analysis includes lead testing. A reverse osmosis system certified for lead removal is the most effective solution. See our Reverse Osmosis Guide 2026.

Arsenic — A Regional Concern in South Dakota

Arsenic is a naturally occurring element that occurs at elevated levels in groundwater in certain areas of South Dakota and Minnesota, particularly in private well water. The EPA maximum contaminant level (MCL) for arsenic is 10 ppb — but health effects can occur at lower levels with long-term exposure. Arsenic is a known carcinogen linked to skin, lung, bladder, and kidney cancers.

Private well owners in South Dakota should test for arsenic regularly. Applied Water Technologies provides arsenic testing as part of our water analysis. Reverse osmosis systems with the appropriate membrane specification effectively remove arsenic to well below EPA limits.

PFAS Forever Chemicals — The #1 Emerging Concern in 2026

PFAS (per- and polyfluoroalkyl substances) — commonly called “forever chemicals” — have emerged as the most urgent water quality concern in 2026. These synthetic chemicals don’t break down in the environment or in the human body. They’ve been found in water sources near agricultural areas, military bases, airports, and industrial sites throughout the Midwest — including locations in South Dakota and Minnesota.

In 2024–2026, the EPA significantly tightened PFAS drinking water limits to 4 parts per trillion (ppt) for PFOA and PFOS — some of the strictest standards ever set. Many water systems are still working to comply with these new limits.

The good news: reverse osmosis systems certified for PFAS removal are highly effective, typically removing 90–99% of PFAS compounds. Applied Water Technologies installs RO systems that meet NSF/ANSI 58 standards, providing reliable PFAS protection. See our Complete PFAS Water Guide 2026.

Iron and Manganese

Iron is extremely common in South Dakota well water and appears in some municipal supplies as well. It causes orange-red staining on sinks, toilets, tubs, and laundry. Manganese causes black or brown staining and has been linked to neurological effects at high levels. Signs of iron/manganese issues include:

• Orange or brown staining on plumbing fixtures and laundry
• Metallic taste in water
• Black or gray slime in toilet tanks (manganese bacteria)
• Water that looks clear when drawn but turns orange after sitting

The Hague Water systems we install are specifically engineered to address iron and manganese alongside hardness — a significant advantage for South Dakota well water.

Nitrates — Agricultural South Dakota’s Challenge

South Dakota’s agricultural economy means nitrate contamination is a significant concern for private well owners, particularly in farming communities. Nitrates from fertilizers and animal waste leach into groundwater. The EPA limit for nitrates is 10 mg/L — but even below this level, nitrates pose risk to infants under 6 months (“blue baby syndrome”) and are associated with other health effects at lower levels.

Reverse osmosis is the most effective method for nitrate removal. Well owners in agricultural areas should test annually.

Bacteria and Microorganisms

Municipal water is treated for bacteria — but private well owners have no such protection. E. coli, coliform bacteria, and other microorganisms can contaminate wells from surface runoff, aging casing, and nearby septic systems. Well owners should test for total coliform annually and after any flooding or nearby construction.

UV purification systems, combined with filtration, provide effective protection against bacterial contamination. Applied Water Technologies offers complete well water treatment solutions including UV systems.

Solutions at a Glance

Getting Your Water Tested — Free from Applied Water

The only way to know exactly what’s in your water is to test it. Applied Water Technologies provides a complimentary water analysis for every household in our service area. Our certified technicians — including Bob Kruger, our Water Specialist — test your water on-site and explain the results in plain language, then recommend the right solution for your specific water chemistry.

We serve all of Eastern South Dakota and Western Minnesota including Watertown, Sioux Falls, Aberdeen, Brookings, Mitchell, Madison, Milbank, and beyond. Schedule your free test: (605) 753-2782.