More than three weeks after flooding knocked out electricity and mechanical systems at a 98-unit senior apartment complex on Madison’s Southwest Side, residents were racking up hotel bills or thinking about moving as they waited for city inspectors and the property’s manager to let them back in. It’s the only apartment complex in Madison still in such dire straits in the wake of Aug. 20 storms that dumped as many as 15 inches of rain on parts of western Dane County. “It’s an experience you think you’re never going to have,” said 71-year-old Joan Graham, who had been living at Prairie Park senior apartments since May. “This has been rough on us.”