TONIGHT A BAY AREA NEIGHBORHOOD IS SINKING FASTER THAN ANYONE EXPECTED, AND WE DISCOVERED THAT FIXING THE DAMAGE MAY MAKE IT EVEN WORSE. KPIX 5'S SUSIE STEIMLE IS LIVE IN MISSION BAY TONIGHT, SUZIE? Reporter: WELL, KEN AND LIZ, THEY HAVE A NICKNAME FOR THIS NEIGHBORHOOD. THEY CALL IT LITTLE VENICE BECAUSE SO MUCH OF THE SIDEWALK HERE IS SINKING. AND THE SINKING SIDEWALKS, YOU CAN SEE A COUPLE INCHES AT THIS CAFE, IT'S A PROBLEM WE'VE KNOWN ABOUT FOR A WHILE NOW. BUT DURING A TOUGH YEAR, BUSINESS OWNERS SAY IT'S GETTING TOO EXPENSIVE FOR THEM TO MAINTAIN. IN SAN FRANCISCO'S MISSION BAY NEIGHBORHOOD, THERE IS A PLACE WHERE THE SIDEWALK ENDS. DEFINITELY LOOKS LIKE THERE'S SOMETHING WRONG, OBVIOUSLY, WITH THE SETTLING. Reporter: AND ENDS AGAIN. SOMEBODY NEEDS TO FIX IT. Reporter: AND AGAIN. EITHER THE SIDEWALKS ARE SINKING OR THE BUILDINGS ARE GOING UP. Reporter: THE SIDEWALKS HERE ARE SINKING. YOU CAN SEE THE GAPS AT JUST ABOUT EVERY SINGLE STREET CORNER. THESE CAN BE A LITTLE MORE COMPLEX THAN PUTTING SOME CEMENT ON THE SIDEWALK. Reporter: RACHEL GORDON IS WITH SAN FRANCISCO'S PUBLIC WORKS DEPARTMENT. SHE SAYS THIS PROBLEM WAS PREDICTED WHEN THE NEIGHBORHOOD WAS ENVISIONED. MISSION BAY IS BUILT ON LANDFILL. WE KNEW GOING IN WHEN THIS WAS BEING DEVELOPED, THESE USED TO BE OLD RAILYARDS. AND IT'S MADE ON LANDFILL. WE KNEW THAT THERE WAS GOING TO BE SOME SETTLEMENT. Reporter: ULTIMATELY, IT'S UP TO THE BUILDING OWNER TO FOOT THE BILL TO SHORE UP THE SIDEWALK. I ALWAYS JOKED, IT'S LIKE VENICE BECAUSE IT COULD JUST BE WATER AROUND THESE BUILDINGS. Reporter: JENNIFER SMITH-DOLAN IS THE VICE PRESIDENT OF OPERATIONS AT MERCY HOUSING. SHE SAYS LONG TERM, THE NONPROFIT CANNOT AFFORD TO CONTINUE TO PAY FOR THIS. THE FIX AND THE AMOUNT OF MONEY WE HAVE AVAILABLE TO MAKE THE FIX IS JUST PROBABLY NOT GOING TO ADD UP. Reporter: SHE ALSO WORRIES THE CONSTANT FIXES COULD BE DETRIMENTAL TO THE CAFE NEXT DOOR. PUT ALL OF THIS ON OUR RETAIL TENANTS WHO ARE ALREADY STRUGGLING IN A REALLY DIFFICULT MARKET, AND ADDING ONE OTHER HURDLE, IT'S DEVASTATING TO THEM. THE STREET IS PUSHING DOWN AND IT'S PULLING THE SIDEWALK. Reporter: LARRY CARP IS A GEOTECHNICAL ENGINEER WHO STUDIED THE NOW INFAMOUS SINKING OF SAN FRANCISCO'S MILLENNIUM TOWER, WHICH SUNK 18 INCHES. HE SAYS THE STRUCTURES IN MISSION BAY ARE MORE SECURE. THEY WERE BUILT TO BEDROCK BECAUSE IT'S A LIQUEFACTION ZONE AND STILL THE MAIN BAY OUTLET FOR WATER FROM ALL THE CITY'S UNDERGROUND STREAMS. SO THE GROUND IS SETTLING. THE STREETS ARE SETTLING. EVERYTHING'S SETTLING, BUT THE BUILDINGS AREN'T SETTLING. Reporter: SO THE BUILDINGS ARE OKAY? YEAH, THE BUILDINGS ARE FINE. Reporter: THE BUILDINGS ARE DESIGNED TO WITHSTAND AN EARTHQUAKE, BUT THE SIDEWALKS AND STREETS AREN'T. THE GROUND IS SINKING FASTER THAN ORIGINALLY PREDICTED AND EVERY TIME A BUILDING OWNER FIXES THE PROBLEM, THEY'RE LIKELY MAKING IT WORSE. REPAVING MAKES THE GROUND HEAVIER, CAUSING SIDEWALKS TO SINK FASTER. IT'S A DIFFICULT PROCESS TO FIX THINGS BECAUSE WHEN YOU FIX THEM IT JUST STARTS ALL OVER AGAIN. Reporter: CITY RECORDS OBTAINED BY KPIX SHOW CALLS FOR REPAIRS ARE STEADILY INCREASING. LAST YEAR 259 SITES WERE IDENTIFIED BY THE CITY AS NEEDING REPAIRS. COMPARE THAT TO AROUND TEN SITES TEN YEARS AGO. MOST HAVEN'T BEEN COMPLETED. IT'S AN EXPENSIVE PROBLEM, ONE THAT ISN'T GOING AWAY, AND FOR THE NONPROFIT, IT'S A BIT UNSETTLING. ANYTHING THAT'S TAKING AWAY FROM, YOU KNOW, PROVIDING AFFORDABLE HOUSING IS ALWAYS A LITTLE DISAPPOINTING. Reporter: ALL THESE COSTS KEEP HEADING UP, WHAT DOES IT COST FOR THE AVERAGE STOREFRONT TO FIX THIS PROBLEM, AND HOW OFTEN ARE THEY REALLY DOING THAT? Reporter: SO LIZ, THE SIDEWALKS HERE ARE SINKING ABOUT A QUARTER OF AN INCH A YEAR, WHICH MIGHT NOT SOUND LIKE MUCH, BUT IT CAN ADD UP OVER THE YEARS. EVERY THREE BY THREE FOOT, THAT'S $217 IF THE CITY WERE TO FIX IT. YOU SEE ON A BIG BLOCK LIKE THIS, IT CAN GET PRICEY. YEAH, AND IT SEEMS IT'S A BAND-AID TO FIX THE PROBLEM. THAT'S NOT REALLY GOING TO STOP IT COMPLETELY. SOMEWHERE -- Reporter: EXACTLY. SOMEWHERE BELOW ALL THAT, MISSION CREEK IS STILL RUNNING, AND THAT'S THE PROBLEM. Reporter: EXACTLY. SUZIE, THANK YOU FOR THAT.
