The lower Susquehanna River has been as much as 13 times saltier than normal, prompting a health alert urging some residents of the Havre de Grace area whose drinking water comes from the river to use bottled water instead.
The low water level in the normally freshwater Susquehanna, resulting from drought conditions, is causing salt water from the Chesapeake Bay to back up into the river.
That, Havre de Grace officials say, is leading to unusually high levels of salt in the drinking water of the old riverfront town and surrounding communities.
City officials have issued an advisory that people on low- or no-salt diets should consult their physicians to determine whether they should switch to bottled water until the level of salt goes down to more acceptable levels.
The salt content began rising on Nov. 6 and reached a level at which people could taste it and began complaining about six days ago, city water operator Sharon Gaultney said.
At its height, the salt level in both city and Harford County water reached about 400 parts per million, Ms. Gaultney said.
On Friday, the level fell to 119 parts per million for city water and 200 parts per million for county water during high tide.
The salt level is lower at low tide, when the salt water recedes into the bay, Ms. Gaultney said. A normal salinity level would be 25 to 30 parts per million.
The level of salinity at which people can taste the difference varies, Ms. Gaultney said.
"I've been in town talking to people and they have haven't even noticed it. And with others, the phones are ringing off the hooks," she said.
The pumping plants for the city and county have pipes that can draw water from the top of the river, where there is less salinity.
But the pumps for the Veterans Administration Medical Center at Perry Point have pipes that draw from the bottom of the river, and on Friday the water it was drawing reached a salinity level of more than 500 parts per million. As a result, doctors have ordered that patients with low-salt diets be given bottled water to drink, hospital officials said.
Although the salt level is gradually subsiding, the only real cure is rain, Ms. Gaultney said.
In August, the lack of rain and high temperatures caused an abundant growth of algae in the Susquehanna River that left the drinking water with a musty taste.