Thames Water Utilities Ltd. is looking to raise at least another $150 million (£127 million) from the private debt markets, according to people familiar with the matter, as the company comes under pressure to fix leaky pipes and prevent sewage from flowing into rivers.

London’s water supplier is taking bids from institutional investors this week for a private debt package in some combination of euros, dollars and pounds, said the people, who aren’t authorized to talk about it and asked not to be identified.