Sudden Loss of Water Pressure
A sudden drop is not the same problem as gradually declining pressure. It means something changed, and the four candidates are a leak, a freeze, a failed valve, or the supply itself.
What to do right now
Do these first. None of them need tools or plumbing knowledge, and they limit what this ends up costing you.
- Look at the meterWith everything closed, a moving meter alongside sudden pressure loss strongly suggests a leak, possibly on the buried service line.
- Check the weather and the neighboursBelow freezing points at ice. Neighbours also affected points at the utility. Both are free to check.
Does this need a plumber tonight?
- Sudden loss with the meter still moving
- Sudden loss during freezing weather
- Sudden loss accompanied by damp or water anywhere
- A loud bang followed by loss of pressure
- Utility works in the street with a known restoration time
- A drop confined to one fixture
- Pressure that recovered on its own and has stayed normal
The four causes
A leak large enough to steal pressure, ice partially blocking a line, a valve that has failed or closed, or reduced supply from the utility.
Ice is the seasonal one and it often presents as reduced rather than absent flow, because a partial obstruction still passes some water. In a Northern Utah winter it should be the first suspicion.
A failed pressure reducing valve can drop pressure to a trickle, and it is a common cause that gets missed because homeowners look for leaks instead.
- A leak, particularly on the buried service line
- Ice partially obstructing a supply line
- A failed pressure reducing valve
- A partly closed main shutoff after recent work
- Reduced supply or works by the utility
Why it can be urgent
Because two of the four causes get worse. A leak large enough to affect pressure is moving a great deal of water somewhere, and a partial freeze can become a full freeze and then a split.
Gradual low pressure can wait indefinitely. A sudden drop should be investigated the same day, and during a freeze it should be treated as an active situation.
What this costs
[PLACEHOLDER: PRICING] Pending from the client.
The diagnosis is quick and the repair depends entirely on which of the four causes it turns out to be.
Questions people ask about this
Pressure dropped and my meter is spinning.
That combination means water is escaping in volume. Shut the main and call. If it is on the buried run outside, closing the house shutoff will not stop the meter.
It happened during a cold snap.
Treat it as ice. Shut the main before thawing, because a pipe that split while frozen will flow the moment it clears.
Could it be the utility?
Yes, and asking a neighbour costs nothing. Utility works and main breaks affect whole streets and are usually known about.
If that is not quite what you have
Not sure how urgent this is?
Describe what you can see and hear. We will tell you whether it needs someone tonight, and what to do in the meantime either way.
Or send it over
Four things and a photo.