City Hall and the Board of Nairobi City Water and Sewerage Company are under pressure to drop the alleged plan to sell the state corporation.
The county assembly has kicked off the investigations into claims the county government wants to sell the water company to a French firm.
On Monday, Kilimani Residents Association petitioned the Water and Sanitation Committee, which was recalled by Speaker Alex Magelo to probe the claim.
The MCAs are expected to rein in the executive to shelve the sale plan.
"We pray that you direct the Nairobi county executive and NCWSC board to stop any plans to enter into an agreement with a private company or create a subsidiary under the NCWSC and or transfer of assets from NCWSC," the petition, signed by Wanjiru Gikonyo, read in part.
City Hall had earlier denied claims it was selling or had intention to sell the water company.
The petitioners also asked the MCAs to probe how two finance directors were dismissed from the company by the board.
They also want the assembly committee to make public the income and the expenditures of the water company.
The group further asked the MCAs to direct the NCWSC board to deploy a skeleton staff to ensure water supply is not interrupted owing to the ongoing workers' strike.
The committee, chaired by Mugumoini MCA Alex Otieno, held its first meeting on Monday.
On Tuesday, the company workers will appear before the panel to provide information on the allegations.
"We want them (workers) to tell us all the problems they are facing and what is causing the dwindling fortunes of the company," Otieno said.
The employees, who have been on the streets for the past two weeks, will be represented by the Kenya County Government Workers Union led by branch secretary Matilda Kimetto.
Kimetto had last Friday claimed they intercepted an unsigned draft MoU between the company's board of management and SUEZ Company from France, stipulating the terms of sale.
They are also protesting against 'refusal' by the board of management to renew contracts of two 'performing' finance directors.
Otieno said his team will also investigate the workers' claims the board is not properly constituted.
It will also look into the company’s financial books after it emerged the board members have spent millions of shillings on foreign trips.
"We understand that the board members, who have been in office for less than a year, have traveled abroad seven times in business class."
"These are serious claims that we are going to investigate," Otieno said.
On Wednesday, CEO Philip Gichuki will appear before the panel.
The board, led by chairman Raphael Nzomo will be grilled on Thursday.