The water off Cruz Bay Beach on St. John and at Princess on St. Croix failed this week’s water quality test by the Department of Planning and Natural Resources, according to a statement from the department Friday.

St. John Administrator Leona Smith said local people occasionally swim at Cruz Bay Beach, which is where the ferry boats arrive, but it is not a popular recreational beach. Her office sits at the Battery, adjacent to Cruz Bay Beach.

DPNR is investigating the matter, but spokesman Jamal Nielsen said that a preliminary look into the issue showed that there is construction in the area that could cause runoff. He also speculated that the influx of sargassum weed may cause problems as it decomposes.

Nielsen said the beach has failed before but its appearance on the list is not as frequent as some others.

Princess Beach, also called Condo Row, on St. Croix, also failed this week’s test but that is nothing new.

“The manhole is in the seawater,” Nielsen said.

While he said that the issue at Princess is under investigation, typically sewage coming from that manhole causes the problem.

Cruz Bay and Princess are two of 43 swimming beaches across the territory tested weekly by DPNR. Nielsen said that when a beach fails early in the week, staff retests two days later.

Nielsen said the tests are done to determine levels of bacteria. None of the other beaches on the list failed.

Last week, all 43 beaches passed the test.