Mechanical equipment contributes to a property’s water usage and cost profile in three major ways:
1) the flow rate of plumbing fixtures; in other words, how much water they are designed to use
2) How well equipment is maintained
3) Water pressure

The flow rate of a plumbing fixture can vary greatly from one property to the next, though follows general rules depending upon when it was manufactured. Prior to the early 1980s, toilets had a flow rate of five gallons or more per flush, while showerheads and faucet aerators used five gallons or more per minute. It was not unusual to have seven gallon toilets and twelve to fifteen gallons per minute showerheads.
In the early to mid 1980s, the standard for toilet flow changed to 3.5 gallons per flush. While showerheads and aerators in this period also tended towards reduced flow rates, they were still around five gallons per minute.

Around 1992 plumbing codes changed, requiring toilets to use no more than 1.6 gallons per flush, and showerheads and aerators no more than 2.5 gallons per minute. In today’s market, this is the flow rate you will find for replacement fixtures. And while early versions of these “low flow” fixtures often did not perform well, today most manufacturers deliver quality performance in their low flow devices.

A new “ultra low flush” standard has emerged, which uses 1.28 gallons per flush. Waterless urinals and toilets, half gallon aerators, and pulsing faucets are receiving wider acceptance in the market place as well.
Older high flow equipment can be upgraded to current flow rates with great payback, sometimes cutting water/sewer consumption and cost in half. Argen offers analysis and products to make this happen for you.
Significant maintenance cost savings are also realized through fixture retrofits, as having new toilets throughout a property reduces this costly service call item.

All equipment must be properly maintained to ensure long term efficiency. Toilet flappers and toilet flush valve diaphragms and gaskets have an expected life of three to five years; their life shortens dramatically in high chlorine content scenarios. Aerators get stopped up with trash, and may be removed by the end user. Showerheads have a longer life expectancy, though also have washers and o-rings that wear out, and may clog from calcification.

Routine preventative maintenance is the key, and is the least costly method for maintaining equipment. Checking flappers, flush valves and faucets during routine filter and smoke alarm inspections is very cost effective.

Low flow toilets are sensitive to the type of flapper and flush valve replacement parts, often needing an original OEM part for continued performance. An off the shelf generic replacement can be a source of fixture failure and can result in substantial increase in flow rates. We often hear the statement “those low flow toilets don’t work right”, then learn that improper replacement parts are the reason, and not the toilet itself.

Water pressure is overlooked at many properties. High water pressure forces more water through fixtures, and can even float a toilet flapper valve open, resulting in double and triple flushing. High water pressure also wears out plumbing fittings and valves, causing premature failure and recurring repair problems. Water pressure gauges are available at most plumbing supply houses, and are easy to use.

Optimum building water pressure is 50 to 80 psi. While the lower the better from a conservation perspective, end user satisfaction and system performance needs to be considered. Anything over 80 psi is typically due to worn out or non-existent pressure regulating valves (PRVs). PRVs may have bladders or diaphragms that wear out over time, and they cannot be adjusted. Larger PRVs can often be rebuilt instead of needing to be replaced.

It is amazing how many times we have been called to check out a property’s high water/sewer usage, only to find water at “street” pressure, which can go up to 150 psi.

Consultation with qualified architects, engineers or plumbers is recommended in dealing with PRV placement; fire and other systems require high pressure for adequate performance.