Tropical Storm Arthur caused an estimated $4 billion to $6 billion in total damage and economic loss across the Gulf Coast after dumping more than 20 inches of rain in some areas.

AccuWeather estimated the financial toll from flooding and property and infrastructure damage as Texas, Louisiana and Mississippi responded with evacuations and state emergency declarations.

Arthur moved inland over Matagorda County, Texas, on the afternoon of June 17 with maximum sustained winds of 45 mph, according to the National Hurricane Center. Gov. Greg Abbott had declared a disaster for 101 Texas counties two days earlier, citing severe storms and flood risks across the state.

In Magnolia, Texas, a 15-year-old died after entering a flooded retention pond, the Montgomery County Sheriff's Office said. 

Ahead of landfall, Houston Public Works drew down Lake Houston and staged flood-prone road barricades as the city's drainage infrastructure prepared for a second straight week of heavy rain.

League City's stormwater crews had spent the preceding days clearing storm drains and culverts, removing debris and inspecting critical drainage infrastructure, it said in a public notice ahead of the storm. After the storm, city crews pumped stormwater from the Mariners Mooring subdivision, and officials attributed standing water on FM 517 to a suspected storm drain blockage rather than a system-wide failure, the Daily News reported. A League City official told the outlet the city's drainage system generally performed as expected, with areas served by the city's Hughes Road drainage project no longer holding water as they once did. 

The New Orleans Sewerage and Water Board said its 25-Hz power system experienced an issue that affected several drainage pumps and potable water pumps, taking the affected drainage pumps offline for roughly 30 minutes to an hour before crews restored service. 

The failed equipment was part of a new $300 million power complex built to prevent exactly this kind of outage, NOLA.com reported. S&WB spokesperson Ceara Labat told the outlet a voltage drop from a new Entergy substation dedicated to the drainage system caused the equipment to trip; Entergy disputed that it lost power to the facility. The same equipment had failed once before, on May 20, during a day with little rainfall, a failure the utility never disclosed publicly. City infrastructure official Steve Nelson confirmed the earlier failure. 

Cottonport and Plaucheville, La., received Avoyelles Parish's highest rainfall totals, 29 and 22.5 inches respectively, NWS meteorologists confirmed during a site visit, according to WAFB. In Cottonport, local officials cut through a road ramp connecting Bayou Rouge and Bayou Dulac to help floodwater drain more quickly from the town, KALB reported. Avoyelles Parish flooding damaged roughly 1,500 homes and 27 bridges and caused at least $17 million in agricultural losses, Rebekah Saari, parish emergency preparedness spokesperson, told The Advocate.

Gov. Jeff Landry declared a state of emergency for Avoyelles, Lafourche, Pointe Coupee, St. Landry, St. Tammany and Terrebonne parishes, the Advocate reported. The declaration activates the state's emergency response and recovery program, allowing for direct state assistance to support operational measures at the parish level, the governor's office told the publication. 

In Kenner, La., police reported 50 to 70 vehicles stalled in high water after 5 to 10 inches of rain fell in a short period.

Mississippi Gov. Reeves declared a state of emergency for at least 10 counties affected by the storm, citing damage to homes, businesses and public property. 

The Anchor Lake Dam in Pearl River County came close to failing June 18 after Arthur's remnants brought heavy rain, prompting evacuations and a flash flood emergency before officials confirmed it had held.

Storm erosion also weakened a section of the Swan Lake Dam in Harrison County, county crews built a temporary barrier ahead of the spillway to limit further damage, MEMA reported. 

As of June 26, Mississippi damage assessments showed 486 homes affected statewide, including 116 destroyed, 134 with major damage, 147 with minor damage and 89 otherwise affected, along with damage to seven businesses, three farms, 70 public roads, two public bridges, three public buildings and six nonprofit utility facilities, the Mississippi Emergency Management Agency said. The agency said assessments were continuing and figures were likely to rise.