Cary water tests soft to slightly hard. The Town of Cary's published Consumer Confidence Report puts finished water hardness in the range of 1.5 to 1.8 grains per gallon (GPG) — meaning a single grain of dissolved calcium and magnesium per 7,000 grains of water, roughly. By the Water Quality Association scale, anything below 1.0 GPG is soft and anything from 1.0 to 3.5 GPG is slightly hard.
If you've been told Cary water is at 5 to 8 GPG, that's wrong. We'll get to why that number gets repeated by local installers in a minute. The short version: most Cary homeowners do not need a dedicated water softener.
The actual numbers
Cary water comes from Jordan Lake. The Cary/Apex Water Treatment Facility on the lake's eastern shore treats it with conventional filtration plus chloramine for disinfection. The finished water leaves the plant at the hardness range the town publishes annually:
- Average hardness: 1.5 to 1.8 GPG
- Calcium: ~20 mg/L
- Magnesium: ~4 mg/L
- Total dissolved solids (TDS): ~120 mg/L
- Disinfectant: chloramine (residual ~2.5 ppm)
For comparison: the national average for municipal water is around 7 GPG. Wake County well water in the rural areas south of Apex runs 10 to 20+ GPG. Cary's number is genuinely low — closer to bottled-water levels than to typical groundwater.
Why the 5 to 8 GPG number you've heard is wrong
If a water-treatment salesperson tells you Cary water is at 5 to 8 GPG, they are either reading from an outdated source or quoting a Wake County average that mixes municipal and well-water samples. Cary's published CCR is the authoritative source for finished tap water, and the numbers there are not 5 to 8.
The confusion has a history. Wake County overall has a real hardness problem in its rural well-water stock. Pre-2010 marketing materials from softener companies didn't distinguish between municipal customers and well customers, so the 5-8 GPG figure got attached to the whole county. Cary, Apex, Morrisville, and Raleigh customers got recommended for softeners they did not actually need.
The honest answer for a Cary municipal customer: at 1.5 to 1.8 GPG, you are not going to see scale on your faucets, your dishwasher is not going to die early, and your soap is going to lather fine. A standalone softener is solving a problem you don't have.
When Cary homeowners do benefit from filtration
Filtration in Cary makes sense for three reasons, none of which is hardness.
First, taste and odor from chloramine. Cary's chloramine residual is around 2.5 ppm, which most people taste as a faint chlorine note in cold tap water. It's especially noticeable when you fill a glass and let it sit for a few minutes. Whole-home catalytic activated carbon filtration breaks the chloramine bond and removes the taste throughout the house — every faucet, every shower.
Second, PFAS at the drinking-water tap. Jordan Lake is fed by the Haw River, which carries industrial wastewater from Burlington and Greensboro. PFAS — the so-called forever chemicals — are documented at trace levels in Cary's finished water. The EPA's 2027 enforcement deadline sets the limit at 4 parts per trillion for several PFAS compounds. A point-of-use reverse osmosis unit at the kitchen sink (NSF P473 certified) removes PFAS reliably.
Third, 1,4-dioxane. This one is specific to the Haw River watershed. It's a probable human carcinogen, it's not removed by standard municipal treatment, and Cary has detected it at levels that vary based on upstream industrial discharges. RO at the kitchen sink handles it; carbon-only filtration does not.
The Cary-specific upstream concern
Most water-quality discussions stop at the treatment plant. The harder question is what's coming downstream from the source before treatment.
Haw River → Jordan Lake → Cary tap. The Haw River drains a large industrial corridor through Burlington, Mebane, and Greensboro before it reaches Jordan Lake. The river has documented 1,4-dioxane discharges from textile and chemical operations. Jordan Lake's PFAS levels are higher than Falls Lake (Raleigh's source) because of the same upstream input.
Cary's treatment plant handles bacteria, sediment, and chlorine residual reliably. It does not remove 1,4-dioxane and only partially removes PFAS. That's not a Cary problem — it's a federal-regulation problem. Most municipal treatment plants in the country aren't designed for these compounds yet. The 2027 EPA enforcement deadline is going to change that, but until then, point-of-use RO is the home-level answer.
The Preston, MacGregor Downs, and Lochmere neighborhoods have been the heaviest concentration of point-of-use RO installs in Cary for exactly this reason. The homes there tend to skew toward families with babies and pregnancies, where the PFAS exposure question is taken more seriously.
What to do next
If you want the actual numbers for your address — your specific PFAS detection levels, your specific chloramine residual, your specific lead-line status — request a free water report. We pull the data from the Town of Cary's most recent CCR and produce a personalized 4-6 page PDF within 24 hours. No in-home visit, no sales pitch, no obligation.
If the report shows your water is fine and a filtration system isn't worth the spend, we'll tell you that. The honest answer for most Cary municipal customers without a baby or pregnancy in the home is that a kitchen-sink RO unit is the only filtration they actually need.