“In 1962, W.L. Schurz claimed to have measured a snake in Brazil of 8.46 m (27.8 ft) with a maximum girth of 112 cm (3.67 ft). One female. reportedly measuring 7.9 m (26 ft) in length, shot in 1963 in Nariva Swamp, Trinidad contained a 1.5 m caiman. A specimen of 7.3 m (24 ft), reportedly with a weight of 149 kg (328lb) was caught in at the mouth of the Kassikaityu River in Guyana, having been restrained by 13 local men, and was later air-lifted for a zoo collection in the United States, but died in ill health shortly thereafter...The estimated weight for an anaconda in the range of 8 m (26 ft) is at least 200 kg (440 lb.)”.
Source: Wikipedia.com.
So yes these animals do get quite large and can grow to almost 30 feet in length. Most of the ones caught are in rivers in Venezuela, it is quite conceivable that they grow even bigger deep in the Amazon jungle.
there has never been a scientifically recorded specimen of any modern snake longer than 24 feet. Trust me, I wish there was. The longest scientifically recorded snake was a reticulated python named Fluffy that died at the Ohio zoo in 2012. She was 23 feet 9 inches long.