when we clear our assignment grid, we re coming back to here. reporter: tonight, first responders canvassing houston. the city s bravest checking on the city s residents. all we re doing is we re going by each house, checking door to door. reporter: they ve rescued more than 7,000 from the floodwaters, working double shifts, while many of their own homes are flooded. fighting fires in chest-high water. we got to go, guys. fire hydrant. reporter: going under to connect the hose. we re about a hose short right now. reporter: using a boat s engine to propel water onto the flames. one firefighter injured here. and tonight, we went back to where we were at during the height of the storm. this is incredible. the last time we were in this neighborhood, it was filled with water, and we could only get through this road on a boat. you can t see if it s a foot or 10 feet. reporter: that night, the jackson brothers helped us get a boat to yvette webb, who contacted us through s