There are many reasons why electronic testing is the favoured option over flood testing. These include:
| Characteristic | Electronic test | Flood test |
| Speed of test | Depending upon build-up, areas tested can be of the order of 1,000sq.m, plus, per day by a single tester |
It would be extremely difficult, if not impossible to test such a vast area.
Once the flood test has been imposed, which can take some considerable time in itself, a minimum of 48 hours is then required before releasing, with constant monitoring below. |
| Accuracy | Traces breaches with pinpoint accuracy in minutes. | Can take days, weeks even months for water to filter through the membrane and concrete deck to manifest below without any indication as to the source. |
| Leak potential | Minimal water usage, so no internal consequences of leaks. |
Potentially major leaks, which will last until and beyond the time when the area is drained.
|
| Environmental | Minimal impact |
Huge potential impact from volumes required in loading and draining.
|
| Structure | No impact |
Major load on structure.
|
| Building services | No impact | Potential for rainwater pipes to fail while draining |
| Scope | Can test sections from horizontal to vertical, as well as complex details. | Flat/ very low slopes only. General test only. |
| Economics | Relatively low cost | High cost due to time required to fill and drain, plus consultant costs in monitoring. Potential for repeat testing to locate source. |
| Impact on contract | Quick handover of certified watertight installation | Slow, slow progress to handover. Leaks in evidence below will delay that. |