When the 58-story building you call home starts tilting and sinking, it makes sense that figuring out the aberrational movement's true cause is a top concern — official finger-pointing be damned. With that in mind, a group of Millennium Tower residents have launched their own investigation to get to the root of the headline-grabbing problem impacting their building. According to the Chronicle, in conjunction with the building owner, the Millennium homeowners association has hired an outside consultant to come in and conduct soil samples in an effort to determine what, if anything, can be done to prevent further sinking — which could eventually go down as far as 31 inches according to new report.

To do this, the homeowners have hired a crew along with geotechnical engineer Patrick Shire to drill three, 260-foot-deep holes into the earth around the building (the cost is reportedly to be split evenly between residents and the building owner) in which to stick measuring devices such as piezometers and extensometers. That this will, unlike placing the supports for the tower itself, require drilling into the bedrock is an irony that is surely not lost on building residents.

“We're not going to speculate on the cause of this," homeowner Evette Davis told the paper and other gathered media yesterday. "We’re not going to speculate on how the building is going to be fixed. We are here to announce today that we are embarking on our own independent investigation, which we hope will bring clarity and allow us to make an educated decision on how to actually fix the building.”

However the cause of the sinking does indeed matter. With a class-action lawsuit seeking $500 million in pay, who, ultimately, is found to be at fault will likely have huge financial implications.

The building developer has blamed the sinking on the construction of the nearby Transbay Transit Center. “For our part, our top priority is getting to a fix,” Millennium Partners spokesman P.J. Johnston told the Chronicle. “We want to prevent any further damage nearby construction may be having, and work with all parties to take appropriate remedial action.”

All previous Millennium Tower coverage on SFist.