Tannin Water Filters

Salt-regenerated anion exchange is the proven whole-house fix. A tannin filter looks and works like a water softener, but runs tannin-selective acrylic anion resin that captures the dissolved organics and releases them to the drain at each brine regeneration. Standard sediment and basic carbon filters will not remove tannins. Confirm tannins first with a lab test (iron tints water yellow too), soften hard water upstream, and expect roughly a 1-point pH drop that an acid neutralizer downstream corrects.

Yes. Tannins are an aesthetic problem, not a health hazard. They are natural organic compounds from decaying vegetation, and the EPA addresses them only through its non-enforceable secondary guideline for color (15 color units). The real costs are stained laundry and fixtures, an earthy or bitter taste, and water that looks like weak tea. One caveat: get the water tested anyway, because the same shallow, surface-influenced wells that pick up tannins deserve a full panel.

At one tap, yes, but it's the wrong tool for the whole house. An under-sink RO membrane rejects tannins at the kitchen tap, yet the yellow water still reaches every shower, toilet, and washing machine, and dissolved organics foul RO membranes over time. Whole-house RO runs $5,000 to $10,000. For tea-colored water at every tap, whole-house anion exchange is the standard fix, with RO as an optional drinking-water polish after it.

Uniform yellow-to-tea color that never settles out. Tannin water is evenly tinted from every tap, hot and cold, often with an earthy or musty taste, and it yellows white laundry. The overnight glass test separates it from iron: color that settles to the bottom is iron or sediment; color that stays dissolved is tannins. Rusty orange stains point at iron (EPA flags it at 0.3 ppm) and black-brown stains at manganese. A certified lab test settles it for $99.

The resin lasts years because it regenerates with salt. Acrylic tannin resin releases captured organics every brine cycle, so a properly regenerated bed typically serves 5 to 8 years before capacity fades; frequent regeneration (every few days) is what protects it from organic fouling. When the bed does wear out, 1 cu ft boxes of replacement resin ($895) rebed the tank without replacing the tank or valve. Ongoing cost is softener salt.

Run the overnight clear-glass test. Fill a glass from the tap and let it sit overnight: color that settles into a layer at the bottom is ferric iron or particulates, color that stays uniformly dissolved is tannins. Stain color helps too: rusty orange-red points at iron (the EPA flags iron at 0.3 ppm for exactly that staining), black-brown points at manganese, and a soft tea-yellow cast on laundry and fixtures points at tannins.

Plenty of wells have both, and the order matters: iron gets treated first. We have read lab reports showing 1.5 ppm iron alongside 1 ppm tannin and told the customer to buy an iron filter, not a tannin system, because at those numbers iron is the problem. The $99 certified tannin test settles the question before you spend system money.

No. A softener's cation resin removes calcium and magnesium; tannins are negatively charged organics that need the opposite resin, a strong base anion exchanger. A tannin filter is the anion-side mirror of a softener: same valve, same brine tank, same salt, opposite chemistry.

The two are best friends in the same treatment train, though. Hardness fouls anion resin and cuts tannin absorption, so on hard wells the softener goes upstream of the tannin unit. That order is non-negotiable in our installs, and it's why the complete package ships both stages matched and plumbed in the right sequence.

Yes, expect roughly a 1-point drop. Anion exchange removes alkaline ions along with the tannins, so a well that comes in at a neutral 7.0 can leave the tannin unit closer to 6.0, which is acidic enough to corrode copper pipe over time. This is real field data from our own customers, not theory.

The fix is an acid neutralizer downstream of the tannin filter, which brings the water back up to neutral. You can also raise pH upstream, but then you'd need to overshoot to 8.0-8.5 to land at 7 after the tannin stage, so downstream is the cleaner install. Send us your pH number and we'll tell you whether your well needs one at all.

Tannins are dissolved organics, not particles, so a sediment filter passes them straight through no matter how fine the micron rating. Activated carbon does adsorb some tannin, but its capacity for large organic molecules is small: a carbon cartridge on tannin duty exhausts in months and the color comes back.

Salt-regenerated anion exchange is the standard fix because the resin bed renews itself: every brine cycle flushes the captured organics to the drain and restores capacity. That's also why we ship acrylic resin specifically; styrene-based beds hold onto the organics at regeneration, foul over a season or two, and develop the classic fishy odor of fouled resin.

More often than a softener. Natural organic matter that sits on the resin too long migrates deep into the bead matrix where brine can't strip it, so tannin systems regenerate every 2 to 3 days at meaningful tannin loads rather than weekly. The metered valve handles the schedule; we set it with you at startup.

It uses ordinary water softener salt from the hardware store, roughly 10 lbs per cubic foot of resin per regeneration. Expect more salt than a softener of the same size because of the frequency: that's the operating cost of keeping the bed clean, and it's a lot cheaper than replacing fouled resin. If a regenerated bed ever smells fishy, a baking soda and salt solution restores it.

Count bathrooms. A 1-2 bathroom home (1-3 people) fits the 6 GPM system with 1.5 cu ft of resin in a 10" x 54" tank ($2,195), or the Fleck 5600SXT on the same bed size ($2,695). A home with 3 or more bathrooms (4+ people) needs the 10 GPM system with 2.5 cu ft in a 13" x 54" tank ($2,895) so simultaneous showers and laundry still get full contact time.

Undersizing is the expensive mistake with tannins specifically, because removal is contact-time limited: push 10 GPM through a 6 GPM bed and the organics simply don't transfer, so color leaks through at peak demand. Very large homes run two units in parallel, which the manufacturer supports; call us and we'll spec it.

A properly regenerated acrylic bed typically serves 5 to 8 years. The variables are tannin load, regeneration frequency, and what else is in the water: iron, hardness, and oils all shorten resin life, which is exactly why pretreatment order matters and why we ask for a full water test before sizing.

When capacity finally fades, you rebed the media only: replacement tannin resin is $895 per 1 cu ft box (Purolite A850 acrylic gel, WQA certified to NSF/ANSI-61), and the tank, valve, and brine tank all stay. It fits our 6 GPM (1.5 cu ft) and 10 GPM (2.5 cu ft) systems, the Fleck 5600SXT, or any standard whole-house tannin tank.