Sand in a well is more than a nuisance. It wears out pumps, clogs pressure switches, valves and appliance screens, and can be a sign that something in the well itself is failing. Fixing it starts with finding out why the well is making sand, not with a filter or a bailer.
Why Washington wells make sand
Much of western Washington draws water from glacial deposits. Washington Ecology describes Puget Sound aquifers as mainly sand and gravel laid down by glaciers during the last ice age. Those loose formations will keep feeding sand into any well that lets it in. The common causes:
- No screen, or a failed one. Washington’s well rules define a screen as a device that keeps loose formation material out of the well. Wells finished with open-bottomed casing, perforated pipe or a corroded screen rely on the formation staying put. NGWA notes perforated pipe is a poor fit for sand-and-gravel aquifers because its openings are wide.
- Fill-in. In sandy aquifers, sediment collects at the bottom of the well over time and can cover the screen. As the fill rises toward the pump intake, the pump starts drawing sand.
- A pump set too low or pumping too hard. A pump near the bottom stirs up settled sediment; an oversized pump pulls water (and sand) toward the well faster. Boshart, a pump-accessory maker, says pumps are normally set at least 10 to 20 feet above the bottom.
- Corroded casing. Holes or cracks in old steel casing let formation material in.
- Poor development when the well was built. If a new well isn’t developed properly, sand grains can stay “bridged” around the screen and later collapse into the pump. New wells often pump some sediment for the first few weeks.
- Falling water levels. In late summer or drought, lower water levels can increase how fast water enters the well and bring in sand that wasn’t there in winter.
Signs and a simple test
Gritty aerators and showerheads, clogged appliance inlet screens, sand in the toilet tank, cloudy water, short pump life and pressure problems are the usual signs. NGWA lists turbidity, lost capacity, taste or odor changes and positive bacteria results as signs a well needs cleaning, and says cloudy water should be tested.
A jar test helps you describe the problem. Fill a clear glass or jar from an outside tap near the well and let it stand. LAKOS, which makes sand separators, says material that settles in under three minutes is the kind a centrifugal separator can remove. Fine silt or clay that stays cloudy needs a different approach. Note the colour: tan sand usually comes from the aquifer, while black or rusty flecks can point to pump wear, corroded steel or iron bacteria.
Start with your well log. Ecology’s well report search shows how deep your well is, how it was cased and screened, and what materials were logged at each depth. A contractor should look at it before recommending anything.
What sand bailing is
A bailer is a long tube with a check valve at the bottom, lowered on a cable from a rig. The operator works it up and down at the bottom of the well so sediment loads into the tube, pulls it up, dumps it away from the wellhead, and repeats. The pump has to be pulled first. Bailing is also a standard step after other cleaning methods, to remove loosened material.
Bailing makes sense when fill has built up toward the screen or pump in a well that is otherwise sound, or to clean out material loosened by redevelopment or chemical treatment.
Bailing won’t fix a failed screen, holed casing, or a pump that is set too low or pumping too hard. It removes the sand that has already arrived, and the sand keeps coming. NGWA recommends diagnosing first, often with a downhole camera, and warns that aggressive cleaning can damage badly corroded casing or screens.
After any work that opens the well, it should be disinfected and the water re-tested for bacteria once the chlorine has flushed out. Tacoma-Pierce County Health Department’s shock chlorination steps say re-testing can take two to three days.
Alternatives a contractor may suggest
| Method | What it does | Good for | Watch out for |
|---|---|---|---|
| Bailing | Lifts settled fill out of the bottom | Fill-in in a sound well | Doesn’t stop sand entering |
| Airlift cleaning | Compressed air lifts water and sediment out; cycling it also surges the screen | Faster removal of fill and fines | Needs enough water above the air line |
| Jetting or surging (redevelopment) | Forces water in and out through the screen to break up bridged sand and fines | Poorly developed wells | Can damage weak screens; not effective on slotted pipe |
| Chemical rehabilitation | Acids and agitation for iron bacteria or scale, then pumping until clear | Lost yield from biofouling | Results can be partial or temporary |
| New screen | Installs a screen inside the casing | Failed screen or holed casing in sand | Licensed well construction (see below) |
| Raise the pump or slow it down | Moves the intake away from the bottom or reduces entrance velocity | Pump set too low or oversized | Needs enough water above the pump; a flow sleeve may be needed |
| Deepen or replace the well | New water-bearing zone or a new well | Unrepairable wells, falling water tables | The most expensive option; licensed work |
A note on liners: Washington’s well rules allow liners only in consolidated formations (bedrock). In a sandy glacial aquifer, the repair is a screen, not a liner. Be wary of a quote for a “liner” in a sandy well.
Filters: protecting the house versus the pump
Surface filters sit after the pump, so they protect your plumbing and fixtures, not the pump itself. If sand is wearing out pumps, the fix is in the well (or a downhole device), not in the basement.
- Spin-down screen filters (for example Rusco or Vu-Flow) spin water inside a clear housing with a mesh screen; grit drops to the bottom and you flush it out with a valve. Rusco’s chart converts mesh to microns: 30 mesh is about 533 microns, 60 mesh about 254, 100 mesh about 152 and 200-plus mesh finer still. Boshart says 100 mesh usually removes sand without much pressure loss; finer silt may need 250 to 500 mesh.
- Centrifugal sand separators (for example LAKOS) have no screen. Water spins, sand is thrown to the wall and collects below for purging. They catch heavier, settleable particles, not light silt or clay. LAKOS installs its residential unit between the pump and the pressure tank and warns against oversizing, because separators need enough flow to work.
- Cartridge filters catch finer particles but need replacing; change them when the pressure drop across the housing climbs, not by the calendar. A spin-down ahead of a cartridge makes it last longer. UV disinfection needs fine pre-filtration to work.
- Downhole separators attach to the pump intake and drop sand back to the bottom of the well. LAKOS claims they extend pump life considerably; bear in mind the sand still accumulates and may eventually need removing.
Placement. Separators and spin-downs usually go between the pump and pressure tank, so sand never reaches the tank. Size them to your pump’s actual flow range, check the pressure loss at that flow, and add shut-off valves on both sides. Treatment order is sediment first, then iron or softening, then UV last.
Permits and licensing in Washington
Washington’s well rules separate cleaning from construction:
- Cleaning is maintenance. Ecology’s definition of “well alteration” covers deepening, hydrofracturing and other work to increase yield or change the well, and says it “does not include general maintenance, cleaning, sanitation, and pump replacement.” Sand bailing, airlift cleaning and surging that don’t change the well appear to fall on the maintenance side. Confirm with your contractor or Ecology’s well construction office if in doubt.
- Screens, liners and deepening are construction. Installing casing, liners or screens counts as constructing a well, and deepening is an alteration. That work needs an Ecology-licensed well driller and a notice of intent filed before work starts.
- Pump work is L&I’s domain. Pulling, resetting or replacing a pump on a domestic well needs L&I plumbing (domestic pump) and electrical credentials. Check the company’s L&I registration.
See well service and rehabilitation companies, companies that list sand bailing and sediment filters and sand separators in the directory, each with license details.
What it costs
There is no authoritative price survey for sand bailing in Washington, so treat these as rough, dated contractor figures and get two or three written quotes:
- A Wenatchee pump company’s June 2026 price guide lists well cleaning and redevelopment at about $1,500 to $4,000, raising or repositioning a pump at $400 to $900, liner or screen repair at $2,500 to $8,000 and pump replacement at $1,800 to $4,500.
- A California driller (March 2023) puts cleaning a shallow well with no major problems at $500 to $1,000, and more involved jobs at several thousand.
Ask each quote to name the method, the well depth, whether a camera inspection is included, how the pump will be reset, and whether disinfection and a bacteria test are included.
Questions to ask before you hire
- Have you looked at my well log? What does it show for casing, screen and depth?
- What do you think is causing the sand: fill-in, a failed screen or casing, the pump setting or the pumping rate? How will you confirm it? Is a camera inspection included?
- Which method are you proposing, and why for my well? Is my casing or screen strong enough for it?
- Where will you reset the pump, and do I need a flow sleeve or a downhole separator?
- Will you disinfect the well afterward and leave me a bacteria sample kit?
- What will you measure before and after (flow, water level, sand), and will I get it in writing?
- Does any of this need a notice of intent? Who files it?
- If it doesn’t work, what’s next and roughly what does it cost?
Red flags
- Bailing sold on a schedule, with no attempt to find out why the sand keeps coming.
- A quote for a new well or aggressive cleaning with no look at the well log, no pump test and no camera.
- A liner proposed for a sandy, unconsolidated aquifer.
- Screen, liner or deepening work with no notice of intent, or pump work by someone without L&I credentials.
- No disinfection or bacteria test after the well has been opened.
- A promise that a house filter will protect the pump.
- A filter or separator sized to your pipe rather than your pump’s flow.
How to tell if it worked
Repeat the jar test: the sand should be clearly reduced and stay that way. Flow should be restored and the water clear. You should get a satisfactory bacteria result once the chlorine is gone. Filter bowls and separator purges should fill much more slowly. Washington DOH recommends testing your well for bacteria and nitrate every year; use that annual check to watch for sand coming back, which means the root cause wasn’t fixed.