Why Does Apex Water Taste Different in Spring?

Triangle Waterworks · informational guide

Direct answer: The Cary/Apex Water Treatment Facility normally disinfects with chloramine, then switches to free chlorine for a few weeks each spring and flushes the system, per North Carolina's guidance for chloramine utilities. Free chlorine tastes and smells stronger than chloramine, which is why Apex water changes for a stretch before settling back. Check apexnc.org for exact dates — and don't wait it out: a whole-home carbon system removes it for good.

Why does Apex water taste different in spring?

Because the disinfectant itself temporarily changes. Most of the year, the Cary/Apex Water Treatment Facility — co-owned by the two towns, with Cary as the lead operating agency — disinfects with chloramine, a stable blend of chlorine and ammonia that holds its residual well across a large distribution system.

Once a year, on North Carolina's recommendation for chloramine utilities, the plant switches to free chlorine only and flushes hydrants and lines throughout Apex, Cary, and Morrisville. Free chlorine is more reactive and has a distinct, pool-like taste and smell most people notice right away — sharpest in the first several days, then easing as the flush finishes and the system returns to its normal chloramine routine.

What is the Cary/Apex annual chlorine switch, exactly?

It's a planned, publicly announced maintenance step, not a sign anything went wrong. The Cary/Apex Water Treatment Facility draws from B. Everett Jordan Lake, part of the Cape Fear River Basin, and treats it through activated carbon, ozonation, coagulation, and sand and carbon filtration before adding chlorine and ammonia together to form the chloramine residual that leaves the plant. Once a year, the Town temporarily stops adding ammonia so the disinfectant reverts to straight free chlorine, then flushes the distribution system. Free chlorine scours biofilm and sediment out of pipes more thoroughly than chloramine does — the taste change is a side effect of a system-wide cleaning, not a sign of anything unsafe.

When does the switch happen, and how do I find the current dates?

The Town of Apex announces the exact dates each year, and that notice — not a fixed date on a calendar — is the reliable source, since the window shifts from year to year. Check the current notice at apexnc.org or Cary's own page on the switch before assuming you're inside or outside the window. If your water suddenly tastes different sometime in spring, that's the first thing worth confirming before troubleshooting anything else in your home.

Is Apex water safe to drink during the switch?

Yes. The switch and the flush that goes with it are themselves part of how the Cary/Apex system stays in compliance — a planned maintenance step, not a deviation from it. EPA sets a Maximum Residual Disinfectant Level of 4.0 mg/L for both chlorine and chloramine, and the plant operates within that limit throughout the year, including during the temporary switch. A stronger taste for a few weeks is a taste issue, not a signal that something is unsafe.

Why does the Town notify aquarium and pond owners before the switch?

Because chlorine and chloramine are both toxic to fish and other aquatic life at levels that don't affect people, and dechlorinators formulated for one don't always neutralize both equally well. During the switch, and for a period on either side of it, the water can carry chlorine, chloramine, or a mix of the two — so the Town gives residents who run aquariums, ponds, or fish tanks advance notice to treat their water accordingly. It's a good reminder for homeowners generally: the disinfectant in your tap water is genuinely different for a few weeks, strong enough to matter to a fish tank even though it's fine to drink.

Does the taste go away on its own, or do I need to do something about it?

It goes away at the tap once the switch period ends — but that also means it comes back on the same annual schedule, on a timeline the Town sets, not you. The alternative is treating the water once it reaches your house, so the taste doesn't return each year regardless of which disinfectant the plant is running that week.

What actually removes the chlorine taste?

Scope is what separates a real fix from a partial one. A pitcher or fridge filter certified under NSF/ANSI 42 can noticeably improve water at the one tap it's attached to — but it does nothing for the shower, dishwasher, or ice maker, all of which carry the same disinfectant. A whole-home carbon stage, installed where water enters the house, treats every fixture at once — the only way to stop noticing the switch anywhere in the home.

A whole-home carbon stage covers both sides of that table with the same equipment — you're not chasing a seasonal spike, you're treating the water supply itself, year-round.

Does fixing the spring taste also deal with anything else in Apex's water?

Yes — disinfection byproducts, which form year-round regardless of which disinfectant is running. The Town of Apex's 2024 Annual Drinking Water Quality Report puts TTHM (trihalomethanes) at an average of 41 ppb, ranging up to 53, and HAA5 (haloacetic acids) at 19 ppb — both within EPA's limits of 80 ppb and 60 ppb, fully compliant, but activated carbon reduces both effectively, the same media that handles the chlorine and chloramine taste. A whole-home carbon stage installed once addresses the spring taste spike, the everyday chloramine taste, and the byproducts, in a single pass.

Does a whole-home system do anything besides remove taste?

The system we install pairs that carbon stage with softening resin in one all-in-one unit — the best of both worlds for Apex homes. The carbon half handles everything above: chlorine, chloramine, taste, odor, and disinfection byproducts, whichever disinfectant is running that week. The softening half handles something carbon doesn't touch — calcium and magnesium buildup. Apex's own 2024 report puts average hardness at 1.9 gpg, and our own testing across the service area measures 1.6 to 3.7 gpg by ZIP code — slightly hard at the low end on the Water Quality Association (WQA) scale the Hach Total Hardness Test Kit uses, and moderately hard at the top, since 3.7 gpg works out to roughly 63 mg/L against the WQA's 60 mg/L line. Water in this range still leaves mineral deposits on faucet aerators, glassware, and inside a water heater over years of daily use, because that buildup is cumulative. A low starting number is an advantage once you soften: the system regenerates less often and runs on less salt.

A few things an all-in-one system changes at once: - Chlorine and chloramine taste and smell gone at every tap, not just the kitchen sink - Disinfection byproducts (TTHM, HAA5) reduced along with the taste - Spotting on glassware and dishes reduced - Scale buildup inside the water heater slowed, since it's driven by the same minerals a softener targets - Softer feel in the shower and laundry, from the softening side of the system

How much does it cost to fix this permanently?

Locally installed whole-home all-in-one systems are sized and installed after a free water analysis. National big-brand installers commonly quote $6,000 to $12,000 for comparable coverage. The right fit for your Apex address depends on household water use and your test result, which is why the analysis comes before any quote.

FAQ

I just moved to Apex and the tap water suddenly tasted like a pool for about a week — is that normal? Very likely. That matches the Cary/Apex Water Treatment Facility's annual switch from chloramine to free chlorine, which many Apex residents notice most in the first week or so and then less as the switch period continues. Check apexnc.org for the Town's current notice to confirm the timing, and know that it settles back down once the switch period ends.

How long does the taste change usually last? It varies year to year since the Town sets the window annually rather than on a fixed calendar date, so the current notice at apexnc.org is the source to check rather than assuming a set number of weeks. Residents commonly describe the taste as strongest in the first several days after the switch and easing from there.

Is it safe to drink and cook with Apex water during the switch? Yes. The switch and system flush are themselves a planned maintenance step, and the plant continues operating within EPA's disinfectant limits throughout. The taste is stronger, which is a taste issue, not a safety issue.

I have a fish tank — do I need to do anything different during the switch? Yes, this is worth taking seriously even though the water is safe for people. Chlorine and chloramine are both toxic to fish at levels well below what affects humans, and the Town specifically notifies aquarium and pond owners ahead of the switch because the water can carry chlorine, chloramine, or a mix of the two during the transition. Use a dechlorinator rated for both chlorine and chloramine during this window, and check the current notice for exact timing.

Will a pitcher filter get me through the switch period? It helps at whatever tap or pitcher you fill it from, if it's NSF/ANSI 42 certified for chlorine and chloramine reduction. It won't touch your shower, dishwasher, or ice maker, all of which carry the same disinfectant during the switch — a whole-home carbon stage is the only approach that covers every fixture in the house at once.

Does an all-in-one system only help during the spring switch, or does it work year-round? Year-round. The carbon stage continuously removes chlorine and chloramine taste and disinfection byproducts, whichever disinfectant the plant is running that week, and the softening side keeps working on mineral buildup regardless of season.

Ready to stop tasting the seasonal change?

Take our 60-second water quiz to see which all-in-one system fits your Apex home — carbon and softening, installed once, working every day of the year.

Related reading: Apex Water Softener Systems | Just Moved to Apex, NC — Water Guide | Water Softener Cost in Apex, NC | Why Does Raleigh Water Taste Different in Spring? | How to Get Rid of Chlorine Taste in Tap Water

Sources

• Town of Apex — Water Quality
• Town of Apex — Annual Water Disinfection Method Switch notice
• Town of Cary — Annual Water Disinfection Change
• WUNC — If your water tastes weird, it might just be a spring clean