The first rupture was reported when an 8-inch water main broke beneath the intersection of Brewster Avenue and Warren Street at about 2:40 a.m., said Xavier Mercado, acting public works supervisor for water.

Water flowed into the basements of two homes, which were evacuated, Mercado said.

Redwood City firefighters responded and pumped out the water and residents were able to return to their homes within a couple of hours, he said.

A second rupture on a different 8-inch pipeline was detected in a residential neighborhood near Allerton and Standish streets at about 6:15 a.m., Mercado said.

No property was damaged and no evacuations were necessary, he said.

The intersection of Brewster Avenue and Warren Street remained closed as of 10 a.m. while public works crews made repairs to the pipe and to a portion of road that was damaged, Mercado said.

The intersection was expected to reopen this afternoon.

Water service to the area was slowed but not cut off, Mercado said. Full service was expected to be restored later today.

A preliminary investigation indicated that the two ruptures, located about five blocks apart, did not appear to be related, Mercado said.

Small earthquakes and changes in weather can often cause the soil around pipes to shift or become unstable, he said.