# Water Filter Replacement Schedule # Water Filter Replacement Schedule: How Often by Type, Brand, and Usage **strong** The capacity is the gallons a part can work through, and the interval is the months a maker allows. Your draw is what turns one into the other. *em* [Filter Replacement Schedule: Read the Numbers](#specs) [Scoring a Filter Replacement Schedule](#score) [What Moves a Water Filter Schedule](#who) [Filter Replacement Schedule Trade Offs](#proscons) [Filter Replacement Schedule Cost](#cost) [Filter Class and Its Replacement Schedule](#compare) [Filter Replacement Schedule: Your Questions](#faq) [Filter Replacement Schedule: Verdict](#verdict) **strong** This article contains affiliate links. **strong** at *em*. **strong** retail prices move daily, so we quote ranges and send you to the live figure on the listing. **strong** *em* Every number on this page traces to manufacturer documentation or a certification record, held against the claims on the box. No free products, no paid placements, no manufacturer relationships. Scoring rules are public on our [methodology page](/methodology). [](https://www.amazon.com/dp/B01LB0L6MS?tag=waterfilternerd-20&linkCode=ogi&th=1&psc=1) ## Water Filter Replacement Schedule: 2 Numbers, 1 Date **strong** Rated capacity is the gallons a part is built to process before the media gives out. Your draw is what your household runs through it in a day. *em* **strong** 45 of the 136 records in this index carry a life figure, and all 45 are written in gallons. *em* **strong** A 200 gallon part in a house drawing 2 gallons a day empties in 100 days. The same part in a house drawing 4 empties in 50. *em* **strong** - The published half: 45 of the 136 records print a gallon figure, from 1 gallon up to 600,000. - The unpublished half: 0 of those 45 files a number of months, so an interval is a claim rather than a record. - The divisor is yours: 1 gallon a day is about what 1 person drinks, so a household of 4 moves 4 times the volume through the same part. - Where the 2 halves split: a 6 month claim on a 200 gallon rating asks for about 364 gallons the part isn't rated to hold. **strong** dividing capacity by draw gives you a date. That date belongs to your kitchen rather than to the box. *em* Think of it this way **strong** The panel says 3 months. Your house decides whether that's 6 weeks or 5 months, and the dust, the pets and the fan hours do the talking. *em* How Long 200 Gallons Lasts Figure showing the days a 200 gallon cartridge covers at 4 different daily draws: 400 days at half a gallon daily, 200 days at 1 gallon, 100 days at 2 gallons, and 50 days at 4 gallons. How Long 200 Gallons Lasts Days, on a 200 gallon cartridge - 0 250 500 half a gallon daily 1 gallon daily 2 gallons daily 4 gallons daily 400 days 200 days 100 days 50 days Rated capacity divided by the gallons a household draws in a day. Individual draws vary with cooking, guests and the season. One cartridge, 4 households, 4 different dates. The capacity is fixed and the calendar is not. Rated capacity against rated capacity: the whole spread is ranked in the long life roundup, which sorts this same field from the top down. See the 800 Gallon Cabinet ## Water Filter Replacement Schedule Scorecard: 4 of 7 for the Longest Clock Every record in this index is rated 1 to 7 across seven verifiable criteria. One point per criterion, no partial credit. The pick for a page about intervals is the part that asks for the fewest of them, and that's Aquasana's AQ-5300+R cartridge. Its card is copied row for row from the review of that part. Four lines take a point and 3 sit at zero, and the 2 document zeros matter more here than the money one. The part publishes 800 gallons and a 6 month interval together, which is rare here. It names 78 contaminants with a reduction figure beside each. What the listing leaves out: 800 gallons at a 2 gallon draw is about 400 days of water. A 6 month clock retires the part at 182, so 436 gallons are still inside it when the calendar comes around. CriterionPointsEvidence Certified removal scope1 point78 contaminants named with a reduction figure beside each, and the PFAS protocol folded into 53 Certification and test transparency0 pointsWQA is named and a Performance Data Sheet is published, and there is no listing number anywhere and the blocks carry no micron figure Filter life and rated capacity1 point800 gallons and 6 months, both published, and the longest rating on this shelf Cost per gallon0 pointsAbout 48 to 52 cents once the interval is applied, roughly 4 times the figure on the box and second only to the ZeroWater part Flow rate and pressure drop0 points0.72 gpm belongs to the assembly, and the cartridge is sold with no flow figure of its own Install and footprint1 pointA quarter turn on a housing you already own, no hoses to disconnect, no plumber Maintenance burden1 point2 changes a year, the fewest on this shelf, against about 6 for the Brita part and about 24 for the ZeroWater one The 4 points are the lines a schedule can be built on, and the 3 zeros are where a date goes soft. The difference between a 4 and a 6 here isn't a cartridge, it's a sheet of paper. The scoring rubric counts a missing listing number as a transparency gap, not a fault. A schedule is only as solid as the smallest number behind it. Compare the 200 Gallon Jug ## What Moves Your Water Filter Replacement Schedule Five things move the date, and 4 of them are habits rather than hardware. How much you drink, how many people you feed, and what the water carries. Then how hard the machine works, and how long the house sits empty. The cartridge is the constant and your household is the variable. Draw is the biggest mover. A 2 person flat and a family of 5 can share the same 200 gallon part. One finishes it a month before the other. Guests are the quiet reason a cartridge dies early. The water itself moves it too. Sediment, iron and hardness load the media faster. A whole house body on a private supply does more work than one on treated city water. The well water roundup starts with a lab test for exactly that reason. Temperature and idle time finish the list. A house that empties for a month barely ages the part, and storage isn't a figure any box prints. #### This Is Not Your Schedule If You want one date for every filter: a pitcher part and a membrane are 2 different clocks, and the map that holds them is the replacement cartridge index. - You want to skip the arithmetic: dividing capacity by draw is 1 line of math, and it's the only figure that belongs to your house. - You want the longest part in the estate: a 100,000 gallon rating is a durability number rather than a schedule, which is why the membrane class prints no life figure at all. The short version **strong** The SPF on a bottle is a lab figure taken at 2 milligrams per square centimeter, and the real number depends on how you use it. *em* [Compare the 100 Gallon Spout](https://www.amazon.com/dp/B0GDJMJ36T?tag=waterfilternerd-20&linkCode=ogi&th=1&psc=1) ## Water Filter Replacement Schedule: What You Gain, What It Costs **strong** You stop throwing away capacity that's still good. You stop drinking through media that's already spent. *em* **strong** A cartridge with an honest gallon figure lets you run the division and stretch the part. On an 800 gallon rating that can be 200 extra days of water. *em* **strong** Change a part 2 months early and you pay for the same water twice. *em* #### What You Get - One division that turns a gallon figure into a date your kitchen can hold. - A reason to stretch a part that is still inside its rating, which is most of the capacity on an 800 gallon cartridge. - A shortlist where the number is published: 45 records of the 136 print a capacity, and the pitcher, spout and cartridge shelves carry most of them. #### What It Costs You - A draw figure you have to estimate, since nobody measures what a household drinks. - The interval, applied 1 class at a time, because a pitcher part and a cabinet cartridge assume different houses. - An early change when the water is hard or the house is full, which no record here predicts for you. The [filter choosing guide](/choose-water-filter) runs the same exercise on standards rather than on intervals. [See the 19,000 Gallon Cabinet](https://www.amazon.com/dp/B083NR5DVY?tag=waterfilternerd-20&linkCode=ogi&th=1&psc=1) ## Filter Replacement Schedule Costs, Priced by the Part **strong** Parts a year is draw times 365 divided by capacity. The band per part is what you'll hand over each time the number comes around. *em* **strong** At 13 to 17 cents a gallon that's roughly $95 to $125 of parts. At 6 to 8 cents it's about $45 to $60. *em* *em* a cheap part on a short interval can cost more over a year than a dear part on a long one, and the gap runs to 4 times. The [cartridge comparison](/best-replacement-cartridges) and the [high flow roundup](/best-high-flow-filters) both sort on that running figure. - Under 20 cents a gallon: the pitcher and spout classes, where a part is cheap and the cycle is short. - About 45 to 60 cents: the under sink cartridge band once the interval is applied to an 800 gallon rating at a light draw. - Under 1 cent a gallon: the whole house bodies, where the cylinder serves every tap and the money is spread over 600,000 gallons. - The year at a 2 gallon draw: about $45 at the bottom of the estate and about $380 at the top. **strong** A 40 gallon jug part and an 800 gallon cabinet part can sit $10 apart on a shelf. *em* Put another way **strong** The card holds 10 punches, and the shop decides when it stops being valid. Draw the water slowly and you walk away with 3 of them unused. *em* [Compare the 40 Gallon Part](https://www.amazon.com/dp/B00004SU18?tag=waterfilternerd-20&linkCode=ogi&th=1&psc=1) ## Replacement Schedule by Filter Class, Side by Side **strong** Divide a published capacity by the printed interval in days. That gives the gallons a day which makes the 2 numbers agree. *em* **strong** A jug part implies about 0.7 gallons a day and a cabinet cartridge about 4.4. *em* ClassA published capacityInterval a box printsThe draw that reconciles themPublishes a life figure **strong**100 to 350 galabout 3 months**strong**6 of 8 Pitcher40 to 200 galabout 2 months0.7 gal a day6 of 18 Refrigerator200 to 300 galabout 6 months1.1 gal a day4 of 11 Replacement part40 to 800 galabout 6 months4.4 gal a day4 of 11 Under sink800 to 22,000 gal6 to 12 months4.4 gal a day10 of 22 Whole house100,000 to 600,000 galabout 12 months274 gal a day3 of 10 Reverse osmosisno life figure filedabout 24 months, membranenot published0 of 18 **strong** For a light draw it's the interval, and for a heavy one it's the capacity. *em* Where the Capacity Figures Land Bars showing how the 45 capacity figures in the index fall into 5 buckets by size: 9 records under 100 gallons, 18 between 100 and 999 gallons, 7 between 1,000 and 9,999, 6 between 10,000 and 99,999, and 5 at 100,000 gallons or more. Capacity by Size, All 45 Records Records, of 45 - 0 5 10 15 20 under 100 gal 100 to 999 gal 1,000 to 9,999 10,000 to 99,999 100,000 and up 9 records 18 records 7 records 6 records 5 records Every life figure filed in the index, sorted into 5 buckets. The field holds a volume in all 45 cases, so no bucket here is measured in months. The same word, 3 orders of magnitude apart. A 40 gallon jug part and a 600,000 gallon cylinder are both filed as capacity, and only 1 of them can be compared to the other without a unit check. The pitcher class, the faucet mount group and the under sink cabinets hold their rows in full. The whole house class is where the 600,000 gallon figure comes from. See the 200 Gallon Fridge Part ## Filter Replacement Schedule Questions How often should I change a water filter It depends on the capacity and your draw rather than on the type alone. A jug part runs about 2 months, a spout part about 3, and a cabinet or fridge cartridge about 6. Divide the rated gallons by your daily draw, and that's the figure that belongs to your house. Does the replacement schedule change by brand Yes, because each brand assumes a different household. Two parts here are both rated 800 gallons, and 1 is sold on a 6 month interval while the other prints no interval at all. The capacity is the figure worth comparing. What happens if I leave a cartridge in too long The carbon is spent before the housing stops passing water, so the taste goes flat and the flow slows. The part keeps working as a strainer and stops working as a filter, which is why the gallon figure matters more than the smell test. Does hard water shorten a filter replacement schedule Sediment, iron and hardness load the media faster. A hard supply or a private well can pull the date forward well inside the printed interval. Softening or a sediment stage ahead of the cartridge, and you'll get some of that time back. Should I replace on the calendar or on the gallons Whichever arrives first. The gallons are the honest figure and the calendar is a backstop. A light household retires the part early, and a heavy one spends the rating before the date lands. ## Filter Replacement Schedule: Where the Dates Land Take the capacity, divide by your draw, and keep the smaller of that answer and the printed interval. That line replaces every schedule on every box in this index. It's the reason the same 200 gallon cartridge can be a 3 month part or a 13 month part without changing at all. Nothing about the cartridge changes, and everything about the household does. Everything else on the box is a suggestion. Among the well documented records, the AQ-5300+R cartridge has the longest clock. It runs 2 changes a year against about 6 for the Brita part. For the shelf where the parts are cheapest and the cycles are shortest, the Brita lineup is the honest start. For a membrane the interval moves to the years column. The pre and post filters carry the 6 month load, which the membrane comparison draws in full. The estate's own spread runs from about $45 a year to about $380 for the same 730 gallons. The schedule is what separates them, and it's the 1 figure you control. Read the capacity, estimate the draw, and write the date down. The main filter index ranks every record on the same 7 lines, and the refrigerator roundup covers the class where the interval works hardest. Open the Longest Clock ### Write the Date Down Rated gallons over daily draw, against the interval on the box, and the smaller number wins. A light house retires the part early. A full house spends the rating first. Check the Whole House Set ## Filter Replacement Schedule: Every Term Named Here Rated capacity: the gallons a cartridge is rated for before the media gives out, and the half of the schedule that gets published. - Replacement interval: the months a maker allows on a part, which arrives from the copy rather than from the life field in any record here. - Draw: the gallons a household runs through a filter in a day, which is the divisor that turns a capacity into a date. - Parts a year: draw times 365 divided by capacity, and the figure that sets an annual parts bill. - Cents per gallon: the band per part divided by the rated capacity, which is the only figure that makes 2 cartridges comparable over a year. - Membrane: the film inside a reverse osmosis body, rated in years rather than in gallons, with pre and post filters carrying the shorter clock. - Media: the carbon block, resin or fiber doing the work, which is what runs out while the housing keeps passing water. - Sediment stage: a coarse filter ahead of the cartridge, which catches grit before it loads the media. - Performance Data Sheet: the document listing what a certified part was tested to reduce, and the strongest paper a box can carry. - Listing number: the serial a certifier publishes for a certified model. No record in this catalog prints 1. ## Keep Reading: Building a Filter Replacement Schedule - The Replacement Cartridge Index: 11 parts in 4 bodies, sorted on capacity and cents per gallon. - Best Long Life Water Filters: the shelf where the interval is the whole argument. - How to Choose a Water Filter: the 4 questions that pick the body before the part. - The Full Filter Index: all 136 records, ranked on the same 7 criteria this page uses.