"Our displaced residents in some of the hardest-hit areas are now able to return to their homes and begin to rebuild their lives," Mayor Ray Nagin said Monday in a statement.
The area encompasses the 10 blocks or so closest to the Mississippi River, where the ground is higher.
In other parts of the neighborhood, people still must boil water before using it to drink, prepare food or bathe, Nagin noted. Officials said they do not know when they'll be able to open those areas.
About 30 to 50 trailers provided by the Federal Emergency Management Agency have been set up on lots where the city has certified that power and safe water were available, said Darryll J. Madden, an agency spokesman. Lack of power and water has kept FEMA from filling 350 other requests in the neighborhood.
The area's water system was badly damaged when houses were flattened or knocked from their foundations, leaving water pouring from pipes and uncoupling water and sewer lines. The stress added more cracks to a system that already needed repairs citywide. The floods also uprooted trees, breaking still more lines.
The announcement does not portend a rush of residents returning to the area. The Lower Ninth remains a wasteland of damaged or destroyed homes and piles of debris.
Moreover, many homeowners won't know for some time whether they'll be able to rebuild. The governor's $7.5 billion plan for helping homeowners affected by hurricanes Katrina or Rita rebuild or move is still in the Legislature. And more than half of that plan depends on $4.2 billion in a federal bill that hasn't cleared Congress yet.
By Janet McConnaughey