Short answer: every 2–6 months for most homes. The exact timing depends on your water, your shower habits, and the cartridge type. Use the quick calculator below to dial in YOUR schedule—then watch for the tell-tale signs it’s time to swap.
TL;DR
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Typical range: 2–6 months
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Heavy use / hard water: closer to 2–3 months
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Light use / soft water: closer to 4–6 months
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Change ASAP if: pressure drops, “pool” smell returns, skin/hair feel worse, or water looks/smells off
What actually determines cartridge life?
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How much water you run
More showers, longer showers, higher flow = faster exhaustion. -
Water chemistry
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Hardness (calcium/magnesium): adds film & scale; clogs sediment stages faster.
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Disinfectant load (chlorine/chloramine): consumes Vitamin C/carbon media sooner.
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Sediment/old plumbing: particles fill prefilters quickly.
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Cartridge design & media
Multi-stage (sediment + carbon/KDF + Vitamin C) typically lasts longer and performs more consistently than single-stage. -
Temperature & flow rate
Hotter water and higher flow reduce contact time with media → slightly shorter life.
The rule-of-thumb calculator (use this once, then set a reminder)
Step 1 — Estimate your daily shower water:
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Showers per day × minutes per shower × flow rate (gallons per minute)
Step 2 — Estimate your cartridge capacity (from product page or your box).
If you don’t have it, use a default 1,500–3,000 gallons for compact multi-stage cartridges.
Step 3 — Life in days = Capacity ÷ Daily gallons
Example:
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2 showers/day × 8 min × 2.0 gpm = 32 gallons/day
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Capacity 2,000 gallons → 2,000 ÷ 32 ≈ 62 days (~2 months)
Tip: Many modern showerheads are 1.8–2.0 gpm. If yours is older or unrestricted, use 2.5 gpm in the math.
Clear signs it’s time to replace (even if the calendar says otherwise)
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Pressure drop or sputtering (media is saturated or clogged)
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Odor returns (that faint “pool” smell creeps back)
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Skin/hair feel worse than right after you installed a new cartridge
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Visible discoloration on sediment screens or unusual taste/smell
When in doubt, swap it out—cartridges are designed to be replaced quickly and cheaply compared to the head.
Special cases
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Very hard water (white spots, heavy scale): Expect the short end of the range; pair with a weekly clarifying/chelating shampoo for hair.
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Chloramine cities: Choose a multi-stage cartridge that addresses chloramine; contact time matters, so replace on the earlier side if comfort fades.
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Well water or older buildings: Higher sediment → replace more often; consider a pre-sediment stage.
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Travel use only: If you install for trips, replace after every long trip or if stored damp for weeks.
Pro tips for longer, steadier performance
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Keep flow reasonable (1.8–2.0 gpm showerheads are efficient and filter-friendly).
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Don’t overtighten—a snug, PTFE-taped connection prevents leaks without crushing seals.
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Flush 30–60 seconds after installing a new cartridge to clear carbon dust.
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Set a reminder based on your calculator result (Calendar/phone).
Your next steps with AquaEarth
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Replacement Cartridges (4-Pack) — swap in seconds; keep a spare so you never shower on an exhausted filter.
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AquaEarth Multi-Stage Vitamin C Shower Filter — compact, renter-friendly upgrade for gentler showers.
Learn more:
FAQ
Q: Can I “revive” a cartridge by rinsing it?
A: No. Once media is saturated, performance won’t return. Replace the cartridge.
Q: My water looks rusty for a minute sometimes—is that the filter?
A: That’s usually building plumbing. Let it run briefly; if it persists or the filter clogs quickly, replace the cartridge and consider a sediment-heavy option.
Q: Does removing a flow restrictor make cartridges wear out faster?
A: Yes—higher flow means less contact time and more gallons through the media. Expect shorter life.