Adding water after fermentation has started

Last night I started a new extract brew. Almost 24 hours later the airlock is showing activity, but I just noticed that my primary bucket is filled to the 5 gallon line, not the 5 1/4 gallon line like it should have been. It was a late night last night when I was adding water to my wort, and I think I may have thought a shadow on the bucket was the actual brew level. It's also possible that some foam was throwing my "reading" off. Could also be the Troegs Perpetual IPAs I was drinking during the process. My OG was almost dead-on if that makes any difference.

My question is this:

It's been exactly 23 hours since I closed the lid to my primary bucket, so is it too late to add the 1/4 gallon of water to make the total volume 5 1/4 gallons?

If it is too late, what are the likely consequences to this screw-up, if any?

Thanks for any advice, I love this forum and the homebrew community.

If the Og is correct, I would not dilute it with water.

If you feel you must, then you could add it at any time. It would be easier for me to add it when it is in the bottling bucket. Make sure it is sterile - boiled for 10 minutes and cooled.

Oh, this just occurred to me. If you bottle and add carbonating sugar to the batch, that would be the perfect time to top off with sugar water. I boil the sugar in the water or wort, then pour in the hot liquid. One quart will cool rapidly in 5 gallons.

I'd leave it, but that's just me. It's not going to hurt your beer as long as it's sanitized, but it will water it down slightly. If it will make you rest easier, just add it w/ your priming sugar, as the above poster said.

Leave the beer alone and measure more carefully next time.

Thanks everyone for the replies. I think I'll just leave it alone. My main concern is that the taste will be off.

I guess I was thinking if I were to add any water, do it now so that I'm maximizing the amount of time with the correct volume. I completely understand it tasting slightly watered down if I add during bottling. I'm new to this though, so I'm not sure of the repercussions of being under volume by a quart of water either.

The airlock is showing constant activity now, and it's been 48 hours. Just out of curiosity, would I screw with the fermentation process if I were to add a quart of sterilized water now?

Thanks again everyone!

Adding water prior to bottling is what the really big boys do. They brew a high gravity and dilute to bottle...of course they have a massive lab to help pull it off.....just go with what you have there, it will be great.