A water company issued a warning for people doing DIY during lockdown after a sewer became blocked with concrete, which will cost £25,000 to remove.
Yorkshire Water said it had dealt with large blockages as a result of people disposing of DIY items in their drains.
The firm blamed the problem on a rise in home improvement work at a time when recycling centres and tips had shut.
People have been reminded to only flush "pee, poo and toilet paper" down the loo.
Mark Hammond, from Yorkshire Water, said: "A lot of people are carrying out home improvement projects and looking for ways in which they can keep busy at home.
"With the usual disposal options difficult to access, a number of people have turned to our water and sewage system to get rid of their excess DIY materials, resulting in blockages and avoidable issues for our engineering team."
Yorkshire Water said it had dealt with several large blockages over the past month including a build-up of concrete in a pipe in West Yorkshire.
After repeatedly trying to remove it with a water jet, engineers will now dig a three-metre deep excavation to try to get rid of the blockage.
Another blockage in Wakefield was caused by a flushed tape measure.
Yorkshire Water said its staff, categorised as key workers, were working around the clock to maintain to the water and sewerage network.
Staff have been educated in social distancing and provided with an increased amount of personal protective equipment (PPE).
However, the firm said there was "still concern that these avoidable blockages are resulting in unnecessary exposure for the public and staff members".
Members of the public have been urged to be "mindful" when disposing of materials such as wet concrete and paint.