It really depends on the nature of your leakage, and the type of leakage you are experiencing. For instance, bathroom plumbing rates can range from $60 to $300 depending if: you need to clear a clogged toilet bowl, or replace a bottle trap for sink, or etc. Water leakage detection – of concealed pipes can cost anywhere from $150 to $250 and above, depending if your property is a HDB, condominium or landed property. The factors affecting the cost would be: the complexity of the job, the urgency of the job, and the additional cost that might be involved, which includes: replacement, installation, other waterproofing add-ons.