Which of these examples in a water conservation technique that also reduces water pollution?

Reduction at source is always the most efficient mean of conservation. By re-think the water usage activity, consider how the pollutant would leak out and require the water cleaning and reduce the leak would yield lesser water consumption and net amount of pollutant release.

It must be noted, waste water doesn't imply the water to be dirty or filled with germ. Water from internal vessel cleaning could be recovered and add back to the mixer of the same product formula long as it is not contaminated with other waste water. For this case, both the water and product is recover and result to net reduce of pollution.