Markham Water Hardness & Quality Report (2026)
Water Hardness
13.6 grains per gallon
Source
river
pH Level
8.5
neutral = 7.0
Lead
0.007 mg/L
✓ Below action level
TDS
551 mg/L
Est. Daily Cost
$0.62
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Markham, your appliances are currently losing 31% efficiency due to mineral buildup.
| Appliance | In Markham | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 1.9 yrs | 8.5 yrs | -78% |
| Washing Machine | 5 yrs | 12 yrs | -58% |
| Water Heater | 6.3 yrs | 15 yrs | -58% |
Regional Water Comparison
How Markham compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Markham, Illinois | 233 mg/L | 8.1 ppt | 🔴 Very Hard | river |
| Hazel Crest, Illinois | 186.5 mg/L | 6.6 ppt | 🔴 Very Hard | river |
| Country Club Hills, Illinois | 273.5 mg/L | 9.5 ppt | 🔴 Very Hard | river |
| Midlothian, Illinois | 116.5 mg/L | 4.2 ppt | 🟡 Moderately Hard | river |
| Homewood, Illinois | 253.5 mg/L | 8.8 ppt | 🔴 Very Hard | river |
National Benchmark
How Markham compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Markham | 233 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Markham's Water Unique?
Local geology and source profile
Markham, Illinois, in Cook County — a Cook County city adjacent to Harvey and Calumet City in the south Chicago metro — receives its water from the Chicago Department of Water Management, drawing from Lake Michigan (Cook County) through the south Chicago metro distribution.
The very hard 233 mg/L hardness and TDS of 551 mg/L reflect the south Chicago metro Cook County Lake Michigan supply's very hard dolomitic character — the Silurian Niagaran Dolomite and Devonian carbonate shelf drainage produce very hard dolomitic water typical of the Cook County Chicago metro communities (compare Justice IL: 133/246 in southwest Cook softer; Shiloh IL: 155.5/419; Markham comparable to the south Cook County hard end drawing from deeper Michigan basin dolomite). The Lake Michigan at Cook County — Silurian Niagaran Dolomite (dolomitic — primary hardness contributor), Devonian carbonate shelf (calcareous — secondary contributor), and Quaternary Great Lakes drift (calcareous — TDS contributor).
At 233 mg/L with TDS 551, Markham's water is very hard. A water softener is strongly recommended to prevent rapid scale buildup. A reverse osmosis system is advisable for drinking water. The PFAS level of 8.1 ppt warrants a certified drinking water filter — the Cook County south Chicago industrial corridor contribute to Markham's elevated readings.
Geology & Source: Markham in Cook County draws from the Chicago Department of Water Management on Lake Michigan (Cook County, south Chicago metro, Illinois) — Lake Michigan at Cook County drains the Great Lakes basin (Silurian Niagaran Dolomite — dolomitic) and Devonian carbonate shelf (calcareous) — Illinois Cook County Lake Michigan Silurian-Devonian dolomitic supply produces very hard water at 233 mg/L with TDS 551 mg/L.