The NOAA uses tidal gauges to monitor multiple coastal locations around the United States. They record their findings and compare them to previous periods. In one report, they found that “U.S. coastal communities saw twice as many high tide flooding days than they did 20 years ago — and the trend of near-record high tides is expected to continue through April 2022, as well as in decades to come” (U.S. high-tide flooding breaks records | National Oceanic and Atmospheric Administration). Regardless of the cause, they believe that tidal levels are rising.