Which of the following strategies will aid in reducing indoor water use?

According to the LEED v4: Building Design + Construction Guide, one of the strategies to reduce indoor water use is to optimize the consumption of showerheads by selecting fixtures that have a flow rate lower than the baseline of 2.0 gallons per minute (gpm) at 80 psi, or a local equivalent for projects outside the U.S. This can help the project achieve the Water Efficiency Prerequisite, Indoor Water Use Reduction, and the Water Efficiency Credit, Indoor Water Use Reduction, by reducing the aggregate water consumption from plumbing fixtures and fittings by at least 20% from the baseline1.

The other choices are not strategies to reduce indoor water use, because:

Designing drip irrigation for landscape is a strategy to reduce outdoor water use, not indoor water use1.

Using high-efficiency HVAC systems is a strategy to reduce energy use, not water use, although it may have some indirect water savings by reducing the cooling tower water use2.

Excluding janitor closets in the building is not a feasible or practical strategy, as janitor closets are necessary for cleaning and maintenance purposes, and may also be required by codes or standards3.