Window Water Tightness Test is part of the testing and commissioning requirement. This is to ensure that there will be no seepage through the window and wall joints as well as precast joints. This testing requires an adequate pressure of water to spray outside the unit with all the windows closed. It would last for at least 20 mins. With this, it helps to minimise the lapse of Consultant checks and declaration. It is also to monitor the suppliers manufacturers and workmanship of materials.