The hex wrench size depends on your disposal model, but 1/4 inch is the most common

Most garbage disposals use a 1/4 inch hex wrench to turn the Allen wrench slot on the bottom of the unit. This is the standard size that comes with many disposals or is sold separately at hardware stores. However, some older or specialty models use 5/32 inch or 3/16 inch instead, so checking your manual or the disposal itself before buying is worth the five minutes.

The hex wrench (also called an Allen wrench or Allen key) is what you insert into the slot at the bottom of the disposal to manually turn the grinding chamber when the unit is jammed. You turn it back and forth to dislodge whatever is stuck — usually a bone, fruit pit, or utensil — without reaching into the chamber with your hand.

If your disposal came with a wrench, keep it in a drawer near the sink. If you no longer have it, a 1/4 inch hex wrench from any hardware store costs between $2 and $8 depending on material and brand. A set of assorted sizes costs $5 to $15 and covers you for future repairs on other appliances.

Key Takeaways

  • The 1/4 inch hex wrench is the standard size for most modern garbage disposals, though some models use 5/32 inch or 3/16 inch.
  • The wrench fits into a slot on the bottom of the disposal and lets you manually turn the grinding chamber to clear jams without reaching inside.
  • Check your disposal's manual or look at the bottom of the unit to see what size slot is there before you buy a wrench.
  • A single 1/4 inch hex wrench costs $2 to $8 at any hardware store, or you can buy an assorted set for $5 to $15.

How to find the right size for your specific disposal

The easiest way is to look at your disposal's manual. The manual lists the hex wrench size in the troubleshooting or maintenance section, usually under "Clearing Jams" or "Manual Operation." If you no longer have the manual, search the model number online — most manufacturers post PDFs on their websites.

If you cannot find the manual, look at the bottom of the disposal itself. You will see a slot or hole in the center. A 1/4 inch slot is about the width of a standard pencil eraser. A 5/32 inch slot is slightly smaller. If you have a hex wrench set at home, try the different sizes until one fits snugly without forcing it. The right size will slide in smoothly and turn the chamber with moderate pressure.

Do not guess and buy a wrench that is too large or too small. A wrench that is too big will not fit the slot. A wrench that is too small will spin inside the slot without gripping, and you will not be able to turn the chamber. Spending five minutes confirming the size saves you a return trip to the store.

Where to buy the right hex wrench

Hardware stores like Home Depot, Lowe's, and Ace Hardware stock individual hex wrenches in the hand tools section, usually near the screwdrivers. A single 1/4 inch wrench typically costs $2 to $5. If you want a backup or a set for other household repairs, a 10-piece or 13-piece hex wrench set costs $5 to $15 and includes sizes from 1/16 inch to 3/8 inch.

Online retailers like Amazon and Walmart also carry hex wrenches, often with faster shipping if you order in bulk. If you need the wrench the same day, a local hardware store is faster than waiting for delivery. Some plumbing supply shops also stock them, though they may charge slightly more than a general hardware store.

If your disposal is still under warranty, contact the manufacturer first. Some companies will send you a replacement wrench for free or at a reduced cost. Check the warranty paperwork or the manufacturer's website for contact information.

How to use the hex wrench to clear a jam

Before you start, turn off the disposal at the wall switch and make sure the unit is not running. Insert the hex wrench into the slot at the bottom of the disposal. Turn it slowly back and forth — do not force it or try to turn it more than a quarter turn in either direction at first. You are feeling for resistance and trying to loosen whatever is stuck, not trying to spin the chamber freely.

After a few back-and-forth turns, remove the wrench and turn the disposal back on for a few seconds to see if the jam has cleared. If water drains and the chamber spins freely, the jam is gone. If it is still stuck, turn off the disposal again, reinsert the wrench, and repeat. Most jams clear within three or four attempts.

If the wrench will not turn at all or turns only a tiny bit before hitting hard resistance, stop. Do not force it — you risk breaking the wrench or damaging the disposal's internal gears. At that point, the jam is likely a large object like a bone or utensil that needs professional removal. Contact a plumber or the disposal manufacturer for the next step.

Material and durability of hex wrenches

Hex wrenches come in two main materials: steel and chrome-plated steel. Steel wrenches are cheaper ($2 to $3 for a single wrench) and work fine for occasional use. Chrome-plated wrenches cost a bit more ($4 to $6) but resist rust better if you leave them in a damp area near the sink. For a garbage disposal, either material will last years with normal use.

The wrench itself rarely wears out. The slot on the disposal is what wears first, usually after many years of repeated jamming and manual turning. If the slot becomes stripped or enlarged, the wrench will spin inside it without gripping. At that point, you may need to replace the disposal or have a plumber install a new grinding chamber.

Frequently Asked Questions

Can I use a different size hex wrench if I cannot find the right one?

No. A wrench that is too small will spin inside the slot without gripping, and you will not be able to turn the chamber. A wrench that is too large will not fit. Spend a few minutes confirming the size before you buy — it takes less time than a return trip to the store.

What if the hex wrench slot is stripped and the wrench spins inside?

A stripped slot usually means the disposal has been jammed many times and the internal gears may also be damaged. Contact a plumber to inspect it. In many cases, replacing the disposal is cheaper than repairing the grinding chamber.

Do all garbage disposals come with a hex wrench?

Most modern disposals include one, but not all. If yours did not come with one or you lost it, buy a 1/4 inch wrench at any hardware store for $2 to $8. Check your manual first to confirm the size for your specific model.

Can I use a hex wrench on a disposal that is plugged in?

No. Always turn off the disposal at the wall switch before inserting the wrench. Even with the switch off, make sure the unit is not running and the chamber is still. Inserting a wrench into a running disposal is dangerous.