Whole House Water Filter Maintenance: A Tank System Owner's Guide

What a Tank-Style Whole House Filter Needs From You

A tank-style whole house filter does most of its own upkeep. On a schedule, the control head on top of the tank runs a backwash that loosens the media bed and flushes trapped grit down the drain. Your part is short: keep the power, drain and clock working so that cleaning cycle actually happens, change the sediment pre-filter every 6 to 12 months, and replace the media bed when it wears out, which is measured in years, not months.

This guide covers tank systems: the tall cylinders filled with loose media, like Crystal Quest® SMART and Eagle systems. If your filter is a row of plastic housings with cartridges inside, our guide to changing whole house filter cartridges is the one you want. Salt-based water softeners have their own routine, covered in our water softener maintenance checklist.

The U.S. EPA's guide to maintaining a home water filter makes the same point every manufacturer does: read the instructions that came with your filter and "follow the installation and maintenance instructions exactly." Your manual wins wherever it differs from the general guidance here.

How a Backwashing Tank Keeps Itself Clean

In a downflow tank like SMART, water enters at the top, passes down through the media bed, and returns up a pipe in the center of the tank, called the riser, to your plumbing. A layer of gravel at the bottom supports the bed. Over weeks of use, the top of the bed catches sediment and fine particles, and the media packs down.

A backwash reverses that flow. Water is pushed up through the bed hard enough to lift and loosen it, and the dirty water goes out the drain line. A short rinse then settles the bed back into place before the tank returns to service. That cycle is what keeps the bed from clogging, channeling or dropping your water pressure.

When the Backwash Runs

Crystal Quest's SMART tanks come standard with a timer valve that runs the backwash on a set number of days. An optional metered valve runs it after a set number of gallons instead. Once the interval is set for your water during setup (your manual covers this), you rarely need to change it.

Most control heads are set to backwash in the middle of the night, commonly around 2 a.m., when nobody is running water. You may hear water running to the drain at that hour, and that's normal. If you want to see a cycle for yourself, most control heads have a button that starts one manually; your manual shows which button and what the display says while it runs.

What Backwashing Can't Do

Backwashing removes trapped particles. It doesn't renew the media. Carbon that has used up its capacity to grab chlorine stays used up no matter how often the tank backwashes, and the same goes for other adsorptive and reactive media. That's why a well-maintained tank still needs new media eventually, and why running extra backwashes won't stretch its life. It mostly sends more water down the drain. Our comparison of upflow and downflow whole house filters goes deeper on how each design handles the bed.

Keep the Power, Drain and Pressure Working

A backwashing tank can only clean itself if three things are in place. When one of them fails, nothing looks wrong at first. The bed just slowly packs and fouls.

Power and the Clock

The control head on a SMART tank plugs into a standard wall outlet. If it's on a switched outlet or a power strip that gets turned off, the backwash never runs. After a power outage, look at the display. If the time of day is wrong, the backwash will run at the wrong hour too, possibly in the middle of your morning shower. Resetting the clock takes a minute; the manual for your control head shows the buttons.

The Drain Line

The drain line carries every backwash out of the house, so it has to stay open. Once a year, follow it from the control head to where it empties. Check that it isn't kinked, crushed behind a shelf or lifted into a loop. A drain line should run steadily downhill with no dips, and most plumbing codes call for an air gap where it empties, so the line never touches the water in the drain. In an unheated garage or crawl space, a drain line can freeze and stop the backwash entirely. Our guide to keeping pipes from freezing covers protecting it along with the rest of the system.

Pressure and Flow on a Well

Backwashing takes more water per minute than most people expect, and bigger tanks need more. Crystal Quest's High Flow tanks, for example, list backwash flows of 5, 7 and 12 gallons per minute across their three sizes. On city water that's rarely a problem. On a private well, the pump has to keep up:

• The well pump's output needs to exceed the backwash flow of the largest tank.
• The pressure switch should turn the pump on at no lower than about 25 psi so the backwash has enough push.
• If you have two or more backwashing tanks, like an iron filter and a carbon tank, their backwash times should be staggered at least two hours apart. Two tanks backwashing together can pull pressure down to almost nothing.

If your well can't meet those numbers, talk to the installer before assuming the media is the problem.

The Sediment Pre-Filter: Your Most Frequent Job

Most tank systems have a pleated sediment cartridge in a housing ahead of the tank. It catches sand and grit before they reach the media bed, which is why it clogs first. On Crystal Quest systems, plan on a new pleated pre-filter every 6 to 12 months, sooner on a sandy well or after any work on the well.

The swap itself is the same job as any whole house cartridge: put the system in bypass, relieve the pressure, change the cartridge, check the housing O-ring, and turn the water back on slowly. The cartridge guide linked at the top of this article walks through each step. Write the date on the housing or in your phone so the next change doesn't sneak up on you. If your system also has a cartridge after the tank, change it on the interval in your manual.

How Long the Media Lasts

Media life depends mostly on how much media you have and what's in your water. A bigger bed simply has more material to wear through. These are the service lives Crystal Quest gives for its whole house tank systems:

Treat those as ranges, not deadlines. Heavy iron, sulfur or chlorine in the feed water, or a big household, pushes you toward the short end. Light use on clean city water can reach the long end. For how tank media compares with every other filter type in the house, see how often to change each kind of water filter.

Signs the Media Is Wearing Out

• The taste or smell you bought it for comes back. On city water, a chlorine taste returning at the kitchen tap usually means the carbon is spent.
• Stains or odors return on well water. Orange or black staining, a metallic taste or a rotten-egg smell that had stopped usually means the bed is no longer keeping up, once you've confirmed the backwash is still running.
• Pressure stays low after the easy fixes. If a new pre-filter and a manual backwash don't bring flow back, the bed may be packed or fouled.
• A water test says so. Testing water before and after the tank is the most reliable check, because some contaminants have no taste or smell at all.

One sign doesn't mean spent media: granules of media in your water or caught in faucet aerators. That usually points to a damaged riser or underbed inside the tank, which is a repair, so call for service.

What Replacing the Media Involves

Replacing the media, sometimes called rebedding, reuses your tank and control head. Only the media inside gets replaced, with no new plumbing. Crystal Quest sells replacement media for its tank systems. On a backwashing tank, the job goes roughly like this. An upflow tank like Guardian has no control head to unplug and no backwash cycle, so skip those parts and rinse the new media as your manual directs.

1. Bypass, unplug and relieve the pressure

   Put the system in bypass, unplug the control head and open a tap downstream so the tank isn't under pressure.

2. Remove the control head and empty the tank

   Unscrew the head from the tank and take out the old media. A wet media bed is heavy, so it's usually scooped or vacuumed out rather than tipped.

3. Keep the riser centered and covered

   Cover the top of the riser while you pour so no media falls inside it, and keep it centered in the tank.

4. Add the gravel and new media

   The support gravel goes in first if you're replacing it, then the new media, filled to the level your manual specifies.

5. Refit the head and refill slowly

   Lubricate the O-rings and reattach the head. Starting from bypass, turn the bypass toward service about a quarter turn at a time over several minutes so the tank fills slowly; your manual shows which valve position to use while the tank fills. Filling too fast is a common way to push media out of place.

6. Backwash before you use it

   Plug the head back in and run a manual backwash to purge air and fine dust from the new media, then rinse and return the system to service.

It's messy, heavy work, and many owners have a plumber or water treatment pro do it. Before you open the tank, check your manual and warranty, and have your system's model and media size handy so you order the right replacement.

Valve Care You Can Do, and What to Leave Alone

The control head and bypass valve don't need much, but a little attention keeps them working when you need them.

• Know your bypass. Some systems have a bypass lever built into the control head; others have three valves on the pipes around the tank. Find yours now, not during a leak. Turn it through its positions once a year so it still moves freely. Our article on using a bypass valve shows the common types.
• Look for drips. Check where the head screws onto the tank, the bypass and the pipe connections. A slow drip at an O-ring tends to get worse, not better.
• Use the right lubricant. Whenever you have an O-ring out, use a silicone lubricant made for plumbing. Petroleum-based products can damage some rubber O-rings.
• Consider a leak detector. Crystal Quest offers a leak detector valve that shuts off the water supply if it senses a leak, which is worth having when the system sits in a finished basement.

Leave the inside of the control head alone. Seals, pistons and motors are repair jobs, and the backwash interval and cycle lengths should match your water, not a guess. If something seems off, or the display shows an error, contact Crystal Quest (or your installer) with your model number before changing settings.

Vacations, Seasons and Well Testing

When you're away for a week or more, a timer valve keeps backwashing on schedule even though nobody's using water. That's fine. When you get home, run the cold taps for a few minutes before drinking. If you put the system in bypass or unplugged it while you were gone, run a manual backwash before returning it to service.

Systems in garages, sheds or crawl spaces need freeze protection for the tank, the pre-filter housing and the drain line. A frozen housing can crack, and a frozen drain line stops the backwash.

If you're on a private well, the CDC recommends testing at least once every year for total coliform bacteria, nitrates, total dissolved solids and pH. Add the things your tank is meant to remove, such as iron, manganese or hydrogen sulfide, and test samples from before and after the tank, and that yearly test also tells you whether the media is still doing its job.

Shock chlorinating the well, or having other work done on it, calls for the bypass too. Put the tank in bypass first, and return it to service only after the chlorine has been flushed from the lines, as your manual directs. Our guide to shock chlorinating a well covers the whole sequence.

A Simple Yearly Checklist

Keep the install date, media size and each service date in one place, like a tag on the tank or a note in your phone. When it's time for new media, those three facts are what you'll need. If you're still choosing a system, Step 6 of our whole house filter buying guide compares upkeep across system types.