From my own experience:

My waters broke at 3am, but we didn't call to tell anyone because a) it was 3am and b) we were having a homnebirth and i knew from the (very light, crampy) ctx it would be hours and hours yet so i went back to sleep. My midwives wanted to know when they arrived (2pm) if and when my waters had gone and had i still been in labour then, i was to begin taking anti-biotics at 9pm as the pead thought it'd be safer to give them and protect DD from potential infection. In fact normally they'd have wanted me to go in and have them IV but my fabulous second MW said "No, she won't transfer for that" so they gave her tablets for me instead.

IN the hospital my midwives came out from the give you 24 hours to GIVE BIRTH (not just go into labour) and then section you (which is why i didn't want to give birth there) but in my homebirth setting they couldn't make me do anything and i was staying put unless i got a fever or DD's heart tones got dodgy.

She was born at 6.20pm so no anti-B's for us anyway. If your waters break then you might want to carefully weigh up the possible benefits of any VE's you have before you have them - if you aren't having ctx you won't be dilating, and putting a hand (even gloved) in there is vastly increasing the risk of infection. I had one VE my whole labour.

Anecdotally:

My sister was born on a Thursday evening. Mum's waters had broken at 2am on Monday. She was a homebirth too and mum called the midwife but since mum herself had been a nurse the MW just told her to take her temperature every 2 hours and not stress. She was mum's 4th baby and mum always said she had to "walk her out" because she just didn't want to budge! She was born at 43+5!!!

My friends mum's waters broke with her 5 days before she was born and there were no contractions for 4 of those days. She was young and naive andjust didn't tell anyone (was scared to go to hossie). My friend was fine when she finally came out!

It's important to remember that for many many women waters don't break until late in the 1st stage or even during pushing. Though i know a fair few people whose broke before i know LOTS more whose broke during labour. It's not that likely to happen and if it does it's no biggie. The only people i know whose babies got infections from this were failed inductions where the Ob broke the water himself.

Bx