RE: Sweet Jesus - Maggots in diaper pail??
I don't know anything about worms, but is there any chance your DH made a mistake? Like maybe it's rice or some half chewed food coming out in the dipes? Or clumps of baking powder, if that was in the pail? Have you had flies or bugs in your house? If not, how could the worms hatch there? Perhaps a grosser question, but any chance your DC has pinworms and that's the source? It's not uncommon.
In my limited experience, I have not heard of this. It doesn't sound like you're leaving tons of poop there, and some people just shake what shakes off and ignore the rest, so plenty of people have more poop in their pail. And diaper service customers usually only pick up once a week, and their customers usually don't do ANYTHING to the diapers, so plenty of people are washing at the same interval with even less pre-treatment.
You may still want to take other posters suggestions, but I don't think anything you did was so wacky or gross. If it was what it seemed to be, I think you just got unlucky.
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DD1 13, DD2 10, and DS 7