A resident from Blk 432B wrote to me and his current MP Ong Ye Kung. He said that some sales personnel from Hydroflux came to his house, and claimed to be doing a HDB-affliliated survey on water quality. They claimed selected households enjoy a package deal on their water filters, which will be installed in future BTOs.
After Clarification with HDB, HDB told us that Hydroflux is NOT an HDB appointed contractor and currently does NOT have any BTO projects with HDB.
So, be careful.