The First State is expected to face tropical-storm-force winds up to 73 miles an hour on Tuesday.
Rainfall is expected to be up to six inches in some areas.
In Delaware City, which sits on the Delaware River, officials rely on water pump systems to mitigate flooding. Crews installed barriers along the sea wall on Monday morning.
"Any time you get coastal storms, you're worried about flooding and you're worried about water damage," said David Baylor, City Manager for Delaware City.
New Castle County Public Works crews checked for debris to make sure there are no blockages ahead of Isaias. At the Carousel Pond, they brought in a pump to keep water levels low and prevent flooding downstream.
"Before every storm, we do preventative maintenance checks on eight of our sub-areas we call drainage checks," said Stacy McNatt, Acting Chief of Construction Support for New Castle County Department of Public Works
At the New Castle County Tactical Operations Center, officials are watching Isaias closely, coordinating with state emergency management agencies and issuing briefings twice a day to local partners.
"We're asking residents to be safe stay safe be vigilant," said Matt Meyer, County Executive for New Castle County.
DEMA encourages residents and visitors to prepare now. Here are some tips for what you can do today:
-Secure loose outdoor items such as patio furniture and grills.
-Clear drains around your house
-Ensure that you have an emergency plan, including where you could go if you need to leave your home.
-Have a plan for how to stay cool if the power goes out.
-Create an emergency kit with items such as non-perishable food, water, and extra medications, to sustain each member of your family plus pets for up to 7 days.
-Make sure to include extra cloth face coverings, hand sanitizer, soap, and disinfecting wipes due to COVID-19.
-Also ensure that your electronic devices are charged and that you have a backup battery bank.
-Finally, stay informed by monitoring the DEMA social media pages, local officials, and local weather. To sign up for emergency alerts go to dema.delaware.gov, and for preparedness tips go to PrepareDE.org