( CNN ) -- Getting cell phone reception in waterlogged New York and New Jersey could get a bit easier . In a rare moment of collaboration , wireless providers AT & T and T-Mobile have agreed to share networks in the challenging days following Superstorm Sandy , allowing customers to use whichever network gets coverage in their areas . The combining of networks will happen entirely behind the scenes , so all customers need to do is dial out . They 'll automatically be routed over whatever network is currently the strongest in their location . How you can help . There will be no roaming charges for customers of either company , and no need to change any settings , rate plan or service agreements . Making calls across the Northeast has been difficult following Sandy , and New York and New Jersey seem to be the hardest hit . According to the Federal Communication Commission , about a quarter of cell phone towers in the 10 states were knocked out by the storm . Repairing these towers will take several days or longer , and continued inclement weather could cause additional issues and repair delays . Some transmission sites that are still working are currently running on backup generators , which carriers hope will last until power is restored . `` Our assumption is that communications outages could get worse before they get better , particularly for mobile , '' FCC chairman Julius Genachowski said on a call with reporters Tuesday . Only a very small number of 911 call centers had lost power , and those calls were being rerouted to working centers , according to the FCC . Post-Sandy water safety tips . The major cellphone carriers have shared varying amounts of information on their service outages following Sandy . Sprint said it was experiencing `` service impacts , '' but that it could not provide a specific number for the amount of people without service . T-Mobile said that in New York CIty , 20 % of its network was down . In Washington that number was 10 % . Verizon 's New York City facilities were severely flooded , and the damages were still being assessed . The carrier said its networks were mostly doing well , but there were serious problems in lower Manhattan and general problems throughout New York City . The company did not give exact numbers for outages . Verizon officials also cautioned that some customers in the Northeast might receive `` all circuits are busy '' messages when trying to make calls because of an unusually large volume of post-Sandy demand on the network . AT & T was the most vague , only saying that it was monitoring its land line and wireless networks and working to restore service . T-Mobile and AT & T did not give a timeline for how long this cross-company cooperation would last . Man faces fallout for fake Sandy tweets . In a related act of corporate generosity , Comcast said it will offer free Wi-Fi to users in areas affected by Sandy , according to CNET .
AT & T and T - Mobile will share networks in New York and New Jersey . Users of the two companies will automatically use the strongest network in their area . The company estimates that a quarter of all transmission towers are down in the areas impacted by Sandy .