Cox has started charging overage fees to customers who exceed their data limits in California, bringing the nation’s third largest cable company a bit closer to nationwide deployment of data caps.

Previously, Cox’s California customers technically had monthly caps, but there was no enforcement of overage fees. Moving forward, Cox subscribers in the state will pay $10 for each additional block of 50GB after they pass the monthly cap.

Customers who signed up for the 1Gbps “Gigablast” service prior to September 26 of this year will get unlimited data plans at no extra charge, while all other California customers will have a 1TB (1,024GB) cap.