Water Meter Surprise!
Updated: Mar 31, 2020
In working with contractors and developers around the city, we have found that one of the most distressing line items that may come up in the design process is the need to upgrade the size of your existing water meter. Depending on how many fixtures you have in a particular space, the cost to upgrade your water service could be between $5000-$25,000.
How do you avoid it?
If you have a heavy fixture load in your building, particularly when flush valve fixtures are being used, it is extremely difficult to avoid having to upgrade. And if you do need to replace the existing meter, there is no way to make it cheaper. The price is set by the municipality and is very unlikely to change. The pricing list for the City of Richmond can be found here.
How often do developments need a new meter?
More often than you would think. We find that often the existing meter is a ⅝” or ¾”. The original owner put in the smallest possible option because it was cheaper, but it severely limits your ability to grow. A ¾” meter is really not capable of supplying anything more than an apartment or a small office with one bathroom.
How do I know what I have?
In Richmond, a call or email to the city Department of Public Utilities will get you the most recent record. Otherwise, you could open the vault at the sidewalk and see if the size is visible on the meter itself. Usually, the size is written right there on the nameplate of the meter.
How can I be proactive?
It will take a little math, but it is relatively easy to get a general idea of the water meter sizing a development may need. Here is a short rundown of how to do it:
STEP 1 - You’ll need a full list of the fixtures to get started. The city has a worksheet on its Water and Sewer Permit Application, but the method is a bit conservative. The International Plumbing Code(IPC) also has sizing guidelines in Appendix E that are more palatable. For the city, as long as it is an approved design by an engineer, the IPC method may be used in lieu of the city’s application method. Go to iccsafe.org and navigate to the public access of the 2012 IPC to get started.
STEP 2 - The first stop in the IPC Appendix E is table E103.3(2). You’ll find a list of possible fixtures and a “fixture unit value” for each type. For our purposes, the important number is the on the rightmost column; The total of the cold and hot water load for a fixture. For instance, you will see that a private showerhead such as in an apartment has a total load of 1.4 fixture units.
STEP 3 - Add up your total fixture unit value of all fixtures. Keep in mind the difference between public and private(apartments and private dwellings) fixtures as well as flush tank and flush valve toilets. If a toilet does not have a tank on top but the bowl connects directly to the water system, it is a flush valve. They have a much heavier load.
STEP 4 - Get a rough estimate of the distance to your furthest fixture. What is the longest run of water pipe to a particular fixture? It doesn’t have to be exact, as we are just trying to get a preliminary idea of sizing needs.
STEP 5 - Open Table E201.1 in the IPC Appendix E. We are going to use the most conservative water pressure assumption for this. The top row is where you will use the number from step 3. What is your furthest run? Use the next highest number available. For instance, if you have a run of 123 ft, use the column for 150 ft.
STEP 6 - Staying in the column of your furthest run distance, find the closest number to your total fixture unit value. Just like with the furthest run, use the next higher option than your load. So if your load is 75 Fixture Units, find the option within the 150 ft column that covers the load. So we roll down to row 8. 84 fixture units will cover our load of 75 fixture units.
STEP 7 - Check the “Meter and Service Pipe” size column that corresponds with that row. In our example, we are in row 8. So for this particular situation, you would need at least a 1” meter. You’ll notice the next column “Distribution Pipe” shows 1 ½”. This refers to the actual main water pipe that comes into the building. What this means is that for a 1” meter to supply that many fixture units, the main pipe inside the building will need to be that size.
So now you have a rough idea of what size water meter you need. Keep in mind that many of these numbers will fluctuate during the design process. Layouts change, fixtures get added or removed, etc. We also haven’t even gotten into the water pressure that is available. That is another big issue(and possible budget line item) that will affect your water design. But it’s probably best to digest one thing at a time.
We hope this is a helpful jumping-off point. Have questions? Shoot us an email at firstname.lastname@example.org
We are all nerds who would be more than happy to chat about water meters with you.