The carrier, which has almost 13 million broadband customers, said it is increasing the monthly data cap on most of its U-Verse service’s Internet plans starting August 21 to one terabyte, or about enough to stream 13 hours of high definition video per day, AT&T (T) said.

The new cap is more than triple the 300 GB allowance that customers on plans with speeds of 6 Mbps or less have currently, and almost double the 600 GB allowance for customers on 12 Mbps to 75 Mbps plans. Customers on plans of 100 Mbps or more already have one terabyte allowance. Customers who exceed the cap in a month must pay $10 for each additional 50 GB.

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The monthly data caps are controversial across the broadband industry as consumer groups and some online services charge that they are intended to limit consumers’ video streaming consumption and protect the market for traditional cable television service. Almost 8,000 people complained to the Federal Communications Commission about Internet data caps in the second half of last year.

In April, the FCC banned Charter Communications (CHTR) from imposing any data caps for the next seven years as part of a deal allowing the company to buy Time Warner Cable and Bright House Networks. A day later, Comcast (CMCSA), the largest cable and broadband provider in the country, announced it was raising its data cap to one terabyte from 300 GB.

The most controversial use of data caps occurs when broadband providers decide to exempt their own digital services from the cap. Comcast, for example, last year didn’t count customers watching its $15-per-month Stream TV online video service against their data caps.