Toilets are turning to into small geysers every time the city of Boulder cleans out sewage lines in a neighborhood.It's called a backflush.Cristy Taylor-Fox said water was spewing out of her toilet Monday morning."I just heard a lot of gurgling noises and I'd never heard anything like it," Taylor-Fox said. She went to check and saw an eruption coming from her commode.She ran over to her disabled neighbor and learned she was trapped on the toilet as the water bubbled over and was covered in water and urine."She was completely soaked, couldn't move," said Taylor-Fox.Taylor-Fox said it's a recurring problem and the city needs to start warning residents when the city will be cleaning."I've never seen this kind of attitude, that this is acceptable to have water from your toilet splashed all over," said Taylor-Fox.But the city said the backflushes happen infrequently and when they do, they're minor."We generally get these complaints four times a year," said Boulder spokeswoman Sarah Huntley.What is happening is that the city trucks are pumping air into sewage lines to clear them of sediment."It's sort of similar to when you put a drinking straw in a cup of water and you blow bubbles into it," Huntley said.But residents said the eruptions are more dramatic and unsanitary and the city needs to start sending out warnings. But Boulder said it can't."It's not a situation where it's happening on a regular basis so the problem with having some sort of a mass notification is that we are out doing this work every day, so it's a resource issue," she added.Once the city gets a complaint in a particular neighborhood, crews start knocking on doors and warning other residents, Huntley said.Wastewater employees plan to check with other cities to see if this is a problem elsewhere.