You mailed the water bill on Tuesday. Three weeks later the utility says it never arrived, and your bank statement shows the check cleared, made out to a stranger, for $4,800 instead of $48. Somewhere between your hand and the post office, a criminal fished your envelope out of the mail, erased your ink with household chemicals, and rewrote the check to themselves. That is check washing, and it has grown from a niche crime into one of the most common ways ordinary households lose money.

The scale is documented. In a nationwide alert, Treasury’s Financial Crimes Enforcement Network reported that banks’ suspicious-activity reports on check fraud topped 680,000 in 2022, nearly double the prior year’s filings, driven largely by mail theft. Postal inspectors have been warning about the same trend for years, and while fewer of us write checks than a decade ago, the people who still do, disproportionately older Americans paying bills the reliable old way, are exactly who the crime targets.

How the crime actually works

It starts with stolen mail. Thieves raid blue collection boxes, sometimes with stolen or copied “arrow keys” that open them, pull mail from apartment cluster boxes and unlocked curbside mailboxes, and occasionally rob or burgle carriers. From a stack of stolen envelopes, the ones containing checks are easy to spot.

Then comes the wash. Common solvents can erase many ballpoint and rollerball inks while leaving the printed check stock, the signature line, and often even your signature intact. The thief rewrites the payee and the amount, then cashes or deposits the check, or sells it. The Postal Inspection Service’s check-washing guidance describes how the scheme works, and FinCEN’s alert notes that stolen and washed checks are also photographed and sold in online marketplaces alongside stolen identity data, which is why one stolen check sometimes turns into a string of counterfeits on the same account.

The cheap defenses that actually work

Start with the pen. Write checks in black gel ink, which soaks into the paper’s fibers and resists the solvents that lift ballpoint ink — a standard recommendation from fraud-prevention experts. A pack of gel pens is the cheapest fraud insurance sold in America.

Then fix the mailing habits. Do not leave outgoing checks in your own mailbox with the flag up; that flag advertises to thieves as well as carriers. Deposit mail inside the post office when you can, or in a blue box close to its posted pickup time rather than overnight or on Sundays and holidays, when boxes sit unattended, per USPIS’s mail-theft prevention tips. Pick up incoming mail promptly every day, and put a hold on it when you travel. USPS’s free Informed Delivery service emails you previews of arriving mail, which catches theft early: if a check-sized envelope was scanned but never landed in your box, you know within a day.

Finally, shrink the target. Every bill you can pay through your bank’s own online bill pay or directly with the biller is a check that cannot be washed. For the checks you still write, review your account activity weekly, not monthly, because speed determines how painful the next section is.

If a check of yours was washed

Move fast, in this order. Call your bank immediately, report the check as altered or forged, and ask to close or freeze the account and open a new one; banks generally must make good on checks paid over a forged or altered instrument when you report promptly, but your own deadlines for reporting are set by your account agreement and state law, and waiting months can forfeit your protection. Put the dispute in writing the same week.

Then report the mail theft to the Postal Inspection Service at 1-877-876-2455 or through uspis.gov, file a local police report, and keep copies of everything for the bank’s investigation. If your identity data may have traveled with the check, add a fraud alert or credit freeze at the bureaus. It is also worth telling the payee, the utility or landlord, quickly, so a “missed” payment does not snowball into late fees while the fraud is sorted out.

One more scenario deserves a mention, because it is how many families discover this crime: an older parent who pays everything by mailed check. If that is your household, the kindest fix is not a lecture about going paperless. It is a pack of black gel pens, a weekly five-minute look at the account together, signing them up for Informed Delivery, and moving the two or three biggest recurring bills to the bank’s own bill-pay service, which mails or transmits payments without exposing the account owner’s handwriting or a raidable mailbox. The habit stays; the vulnerability goes.

The bigger picture

Checks are not going away, and neither is the mail. The realistic goal is to make your checks the hardest ones on the block: gel ink, smart drop-off timing, daily pickup, electronic payment where it is convenient, and weekly eyes on the account. None of it costs more than a few dollars, and the people running this crime are, above all, volume operators. They wash the easy checks.

This article was produced with AI assistance and reviewed by a human editor. Figures are linked to their primary sources; where a claim could not be verified from the public record, we say so.