An old bath filter looks exactly like a new one. The water still flows, the tub still fills, and your kid is back to soaking in chlorine. Here's how often to change a bath filter, and how to know for sure.
Change your bath filter cartridge every 3 months. That keeps the filter at full strength, bath after bath. A Tubo Replacement Bath Filter is $34, and if you subscribe, it ships automatically every 3 months at 25% off with free shipping.
Why do bath filters need changing at all?
A bath filter works by catching or breaking down chlorine as water pours through it. A fresh cartridge every 3 months keeps that media at full strength, so every bath gets the same filtered water.
The tricky part: an old filter looks almost the same as a new one. You just stop getting the benefit. The dry patches creep back, the itch after the towel returns, and you don't know why. A set schedule beats waiting.
Water experts agree. The UK's Drinking Water Inspectorate advises changing home filter cartridges on the maker's schedule.
Want to know what's actually inside a bath filter and how it removes chlorine? That's covered in do bath filters actually work?
How often should I change my Tubo bath filter?
Every 3 months. That's the schedule that keeps the Tubo 2.0 Bath Filter's Neutralyx™ Blend removing up to 99% of chlorine and heavy metals, plus chloramine, bath after bath. The housing stays on your spout. Only the cartridge gets swapped, and it takes seconds.
Why not stretch it? Because a tired cartridge fails quietly. The tub fills the same, the water looks the same, and your kid is soaking in chlorine again. One clear schedule means you never have to guess.
| Your household | What it means for the filter | What to do |
|---|---|---|
| Daily baths, or several kids | Lots of water through the cartridge | Every 3 months. Subscribe so you never run late. |
| Hard water or lots of sediment | Minerals and grit collect in the screen and media | Every 3 months, and watch for flow changes. |
| Chloramine or high chlorine in your city | More disinfectant for the media to break down every bath | Every 3 months. Check with total chlorine strips. |
| A few baths a week | Less water, but the media still ages | Every 3 months. Same easy schedule. |
Curious how much disinfectant your city uses? We looked it up for America's biggest cities: chlorine levels in tap water by city.
What are the signs a bath filter needs replacing?
The chlorine smell is back
A fresh filter takes away that "pool" smell as the tub fills. When it's back, the media is used up.
A test strip shows chlorine
The most reliable home check. If filtered water reads close to straight tap water, it's time.
The flow has changed
Slower flow can mean the sediment screen is clogged. Any big change from normal is a reason to check the cartridge.
It's been 3 months
No signs at all? Swap it anyway. A fresh cartridge keeps every bath at full strength.
Skin was doing better and now it's dry or itchy again? Check the filter date first. It's the easiest thing to rule out.
How do I test my bath filter with chlorine test strips?
Chlorine test strips are cheap, easy to find, and take a minute. Here's a quick home check:
What's the easiest way to remember?
Most people don't forget on purpose. A few months just go by fast. Three easy fixes:
A fresh cartridge ships automatically every 3 months at 25% off with free shipping. When it lands, you swap it. No reminders, no reordering. Pause or cancel anytime.
Set a repeating 3-month reminder on the day you install. Write the date on a strip of tape on the housing too.
A 3-month schedule lines up with the seasons. New season, new cartridge. Easy to remember.
Set up subscribe & save on the replacement filter page. New to Tubo? Start with the Tubo 2.0 Bath Filter ($64).
“I love this the water looks cleaner and clear”
Filtering the shower too? Tubo shower filters run on the same 3-month rhythm: how often to change a shower filter. Still choosing a bath filter? See the best bath filter for eczema, and check it'll fit your spout first: will a bath filter fit my tub?
Fresh cartridge, filtered bath, soft skin. Subscribe and it shows up every 3 months at 25% off with free shipping. Trusted by 50,000+ families, rated 4.7★ from 580+ reviews. Subscribe to replacement filters →
Frequently asked questions
How long does a bath filter last?
Replace a Tubo bath filter cartridge every 3 months. A fresh cartridge keeps it at full strength.
What happens if I don't change my bath filter?
Once the media is used up, chlorine passes through to the bath, so you lose the benefit. That's why the UK Drinking Water Inspectorate advises sticking to the maker's schedule.
How can I tell if my bath filter is still working?
Smell the water as the tub fills, and use a chlorine test strip on tap water and filtered water. If they read about the same, replace the cartridge.
Does hard water change the schedule?
Stick to every 3 months and watch the flow. Minerals and sediment collect in the screen, so a big drop in flow is a sign to swap early.
Does a fresh Tubo cartridge work right away?
Yes. Swap it in and the very next bath is filtered, with up to 99% of chlorine removed as the tub fills. Subscribe and the next one ships automatically in 3 months.
Can I clean and reuse a bath filter cartridge?
No. Rinsing won't restore the media that removes chlorine. Once it's used up, it needs replacing.
- US EPA — Chloramines in drinking water. epa.gov
- CDC — Water disinfection with chlorine and chloramine. cdc.gov
- Drinking Water Inspectorate (UK) — Domestic water filters and softeners (maintenance and cartridge changes). dwi.gov.uk