Severn Trent says it hopes it will get rid of a midge larvae infestation at one of its treatment plants in Leicestershire by this weekend.
Lesley Gutteridge spotted the larvae in the baby's bath water
Many residents spotted the tiny worm-like creatures in their household water supplies.
The company said it had had around 230 complaints - and admits 30,0000 homes across the county may be affected.
An investigation is currently underway and employees are doing all they can to flush the worms out.
So far Severn Trent is investigating reports from homes in the south of the county, including Oadby, Wigston, Glenfield and Leicester city centre.
Lesley Gutteridge, from Braunstone, noticed the creatures when she was bathing her 10-week-old son James.
Officials say chironimids are not harmful to humans
"I couldn't believe how many were swimming around in the bath... I noticed they were all in our drinking water in our cups and glasses.
"So I realised that we'd probably been swallowing them as well and I felt sick. You feel just disgusted knowing that you've been drinking worms in the water and that the baby had them all wriggling around him in the bath."
It is understood the chironimids - or midge eggs - got into the water supplied from the Staunton Harold reservoir, and the outbreak has been traced to the Melbourne Water Treatment Centre right next to it.
The water company says they pose no risk to human health.
David Wickens, of Severn Trent, said: "We've not seen anything like this in the Leicestershire area for many years - probably in excess of 10 years.
"We had no advance warning that it was coming and so it's taken us quite by surprise but we think we're on top of it now.
"We think the process we've got here, which is basically to starve them of oxygen by taking these tanks out of commission for a period of days will sort the problem out."
Severn Trent said it would continue to flush pipes out on all streets where these worms have been found.
But meanwhile householders are advised that, in they do find anything unusual in their water, to run their taps for 15 minutes and contact the water company.