Guide · recordkeeping
Correcting logbook entries
Short answer
Draw one line through the wrong entry so it can still be read, write the correct value beside it, then add your initials, the date and a short reason. Never erase, overwrite, use correction fluid or remove pages.
The original stays readable; the correction is initialed, dated and explained.
The four rules
- Keep the original readable. A single line through it, never scribbled out.
- Write the correct value beside it, not over it.
- Initial and date the correction. The person correcting it, on the day they did it.
- Say why. “Transposed digits”, “misread meter”, “wrong column”. A few words is enough.
These are long-standing recordkeeping conventions rather than one federal rule. The point is that anyone reading the log later can see what was written first, what it was changed to, by whom and when. That's what makes a corrected record trustworthy rather than suspicious.
Late entries
If you took a reading but wrote it up later, record the time the reading was taken, not the time you're writing, and mark it as a late entry with the date and time of writing. An inspector comparing your log with your coliform lab slips or pump run times will expect those times to line up.
Why logbook rules are strict
Some states write the standard into rule. Ohio requires operating records to be kept in a way that guarantees their authenticity and accuracy: hard-bound books with numbered pages, or computer logs that automatically record the date, time and person making each entry and prevent erasure or deletion (Ohio Adm. Code 3745-7-09). Whether your state has a rule like that or not, a log kept to that standard holds up.
Corrections in an electronic log
In an electronic log the same principle becomes an audit trail: the software keeps the original value, the new value, who changed it and when, and ideally why. What to look for, and what to ask your regulator, is in electronic vs paper logbooks.
Questions
Can I use white-out or tear out a page?
No. Anything that hides or removes the original entry makes the record look altered, even when the correction was honest. Strike through with a single line so the original stays readable, and never remove pages from a bound logbook.
I forgot to write a reading down. Can I add it later?
Yes, if you actually took it and know the value, but mark it as a late entry: write the reading with the time it was taken, and note the date and time you entered it. Never fill in a reading you didn't take.
What if I missed a reading completely?
Leave the space blank and note why: "not sampled, operator ill", "well house inaccessible, flooding". A gap with an explanation is far better than a made-up number.
Sources
Last reviewed September 28, 2026. Rules change and states add their own; confirm with your state drinking water program.