Main water line-too small?

Main water line coming into the home in the photo is 1/2". (This is a 4 bedroom, 2 1/2 bath, + kitchen). From what I’ve read, standard size should be at least 1" or larger. Is that right?
Didn’t notice any functional flow issues…
Thank you

Are you sure that’s the main water line? Public or private service, any further back photos?

(Sorry for the fuzzy photo)
Circled in red is where this water line comes in.
Here’s why I believe it’s the main- 1. Below grade. 2. Just outside the window is where the metal city lid is located (this is public water). 3. And the line feeds right into the water heater.
Original question- if this is the water main, is it ok if it’s 1/2" ?
Thank you

If that is the main, then yes I’d say it’s smaller than current industry standards recommend.

1/2" should only be found on very very old houses with upgrade recommended. Been using 3/4" here since at least 1950s All new construction get 1" or bigger. 1/2" is about 4 fixture units or 1 bathroom.

Then exactly why and what will you recommend? The only time to report an item that is performing is when it is unsafe due to materials or construction. (ie. improper fasteners, lack of railings, no flashings, improper wiring, etc.) A larger water entry pipe is an upgrade. Agents will disregard upgrades and you will suffer a reputation hit.

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How exactly did you determine this? did you test static water pressure? Did you run dishwasher, clothes washer, and 2 showers at the same time?

Those two photos are not the same location!

Who you tryin’ to scam??


Yes- I ran all first floor plumbing- 2 bathrooms (2 toilets, 2 sinks, 1 shower) and kitchen (sink + dishwasher) continuously for an hour straight.
Pressure wasn’t great when all were running, but I chalked that up to it being an older home.

Here’s a draft of the comment I have in progress for the report:
The main water line was 1/2-inch in diameter. Modern standard size is 1-inch or larger.

The concern here is that the pipe could be undersized and may not be able to serve the needs of the occupants.

Since the inspector is not an HVAC specialist, he recommends a full evaluation of this by a licensed plumbing contractor to see if, 1. this is indeed the water main for the home, and 2. repair or replacement is needed.

Photo 1 is from in front.
Photo 2 is from the side


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The red you see in photo 2 is a faucet located above/past the water main.
You can’t see the water main lever on photo 2 because it’s in the open position on the other side of the pipe

The gate valve is above the ball valve?

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Yes. The main is a ball valve. The faucet past it (red fuzzy object in photo 2) is a gate valve

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I see what you’re saying it’s a boiler drain installed over the ball valve. OK got it :slightly_smiling_face:

To answer your question I can’t think of any jurisdiction in the United States that has a water main smaller than 3/4”. This includes UPC and IPC.

You guys argue all you want;

“The water service line appears to be of a smaller diameter than what is used in today’s plumbing standards. This may cause a reduction in water pressure when using various components at the same time. It is recommended that the service line be further evaluated by a licensed plumbing contractor as to the adequacy of the supply line and water flow.”


Pressure should remain the same, volume will be different.


Might want to tweak that a bit before you publish the report.


Thanks! And I stand corrected. :wink:


Your hearts in the right place Thomas just a little flip-flop verbiage

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