Written Answer by Ministry of National Development on water seepage issues after heavy downpours and water leakage incidents in HDB flats

Feb 1, 2021

Ms Ng Ling Ling: To ask the Minister for National Development (a) whether the Ministry collates from Town Councils and HDB on the number of blocks and units with residents reporting water seepage issues after heavy downpours; and (b) what is the average turnaround time that such water seepage issues are completely resolved.

Assoc Prof Jamus Jerome Lim: To ask the Minister for National Development (a) what is the reported number of water leakage incidents in terms of equivalent dwelling units (EDUs) or per 1,000 blocks of HDB flats for each five-year period between 2000 and 2020; and (b) whether any study has been performed to identify the causal reasons for such incidents.

Answer:

Water seepage into flats after heavy downpours can be via the external walls of the flats, or via the rooftop, for flats located on the top floor.  This is generally caused by wear and tear of the external walls and roofing material of HDB blocks, resulting in small cracks that allow water to seep through.  The external walls and roof tops of HDB blocks are common property under the Town Councils’ management and maintenance.  Residents who encounter such water seepage issues typically report them to the Town Council managing their estate.  MND does not collate data from Town Councils on the total number of such water seepage cases that are reported to the Town Councils, or the turnaround time that Town Councils take to completely resolve the cases.  Nevertheless, if Town Councils face difficulties in resolving such cases, HDB will work with the Town Councils to resolve them by carrying out joint inspections and providing technical advice.

For water seepage cases that have been reported to HDB directly and referred to Town Councils, the data is as follows:
a. For water seepage via external walls, HDB received an average of 11 cases per 1,000 dwelling units (DUs) over the 5-year period from 2011 to 2015, and 15 cases per 1,000 DUs over the 5-year period from 2016 to 2020. 
b. For water seepage via roof tops, HDB received an average of 1.7 cases per 1,000 dwelling units (DUs) over the 5-year period from 2011 to 2015, and 1 case per 1,000 DUs over the 5-year period from 2016 to 2020.

Water leakage can also occur as a result of water seeping from the floor of the upper floor unit to the ceiling of the lower floor unit.  The cause of such leaks is generally wear and tear over time.  HDB received an average of 104 cases per 1,000 DUs over the 5-year period from 2011 to 2015, and 105 cases per 1,000 DUs over the 5-year period from 2016 to 2020. 

HDB does not have readily available data on water seepage cases before 2008.