FREAK Shots: The Sacred Hydrant

Freakonomics reader Rich Beckman took this photo in Washington, D.C. on the grounds of the Capitol building:

Fire HydrantPhoto: Rich Beckman

Then he asks a natural question: “If the hydrant isn’t working, what does it matter if someone parks there?”

Dubner asked a similar question on this blog: why is parking in front of fire hydrants prohibited in the first place (hoses are flexible for a reason), especially as parking becomes a rare commodity?

Maybe as a start, hydrant spots — following RexCorp’s example — can be reserved for hybrid drivers only.

(Send your FREAK-worthy photos here.)


With respect to the color, it does not indicate pressure - it indicates flow. It's the amount of water the hyrdrant will supply at 20 psi residual pressure, meaning the fire pump (in the fire truck) has pulled the water pressure down to its lowest acceptable level above pipe-collapsing vacuum, using a non-collapsing "hard suction" hose connection. It is only a relative indicator of how much water can be obtained when using just the pressure of the hydrant.

As to the reader who thinks "modern" fire departments can use GPS to find hydrants - define modern. GPS has only been reliable in street mapping locations for

Rich Beckman

Just for the record. Here is a pic that gives some context to the fire hydrant. There is a car parked adjacent to the hydrant.

The other hydrants in the area did not have a No Parking sign in front of them.

Jack Sprat

Sure, park the bike. They are MUCH easier to crush and toss out of the way when firefighters need to get to the hydrant. Speed is EVERYTHING in firefighting.



Well, the logical answer might be that the "No Parking" sign was there before the hydrant went out of service, but I still want to know where the sign asking dogs to refrain from relieving themselves is.


Dude, you can't park in front of a hydrant SO THAT THE HYDRANT IS EASIER TO FIND! So that the fire department doesn't have to spend 10 minutes looking for the thing being blocked by somebody's SUV while the building burns down.



As a Washingtonian, I'd say that parking is prohibited all over the place near the Capitol now, largely out of fears of terrorism. This spot is probably banned because it's near that building, not because of the defunct hydrant.


I can think of a few valid reasons for this. The most likely are:

1. They're planning to do some work on the street or sidewalk; water's been shut off, and parking prohibited, in anticipation.

2. The hydrant -- or water service in its vicinity -- is malfunctioning, and they plan to work on it.

Granted, these are sound, rational reasons to prohibit parking in front of a non-functional hydrant. Government rarely, if ever, does anything for sound, rational reasons. So I cannot guarantee that these account for the photo. They're merely possibilities.

Jeff S.

Who decided that hybrids help the environment?


@#12: i had no idea youre not allowed to park in front of fire hydrants. be careful when making broad statements about "everyone's" level of knowledge.

thank you freakonomics for potentially saving me from a ticket!


Another question, why motorcycles are not allowed to park at the hydrants? You can talk about cars, but motorcycles for sure make no obstacle for the use of the hydrant.

Pete Ehlke

Who says that hoses are flexible? Have you ever tried to manipulate a pressurized firehose? They're much closer to treetrunks than they are to your garden hose.

The canonical reason why it's illegal to park in front of hydrants is given by

MITBeta @

Those blue dots that the Californians have are not universal. For example, things like "turtles" and "clams" on the road in some areas of the country don't work in places where it snows and plows are required.

Hybrid cars: Since they're so fuel efficient, shouldn't we make it harder for them to park so that the gas guzzlers can be turned off sooner?

Original question: Could it be that if somebody parks in front of the hydrant, and then the hydrant is subsequently repaired, the parker will be in violation? Though I'm not familiar with any rule that says one is allowed to park in front of an out of service meter anyway.


Run a hose over, around, or through a car, then open the high-pressure valve, get a damaged car.


DJH (9:46 a.m.) wrote:
I can think of a few valid reasons for this. The most likely are:
1. They're planning to do some work on the street or sidewalk; water's been shut off, and parking prohibited, in anticipation.
2. The hydrant - or water service in its vicinity - is malfunctioning, and they plan to work on it.

You clearly don't live in D.C. Your comment is a very optimistic view - and totally unrealistic here in the nation's capital. In reality, the water commission has started putting these signs on the broken hydrants after a few incidents where firefighters showed up to fires only to find the hydrant was dry. Now, at least, they show up to the hydrant and know it's futile to hook up to it. (And, they learn that faster when there's not a stinking SUV parked in front of it.)


I am a volunteer firefighter and would like to offer some insight...

The color of a hydrant typically tells the pump operator how much water pressure is available at the hydrant. There is a wide range of available pressure at hydrants, so it helps the pump operator to know the ball park of what he may get.

Taking time to move a car or bust windows to get to a water source jeopardizes lives. The way we run our assignments, the first engine in has 750 gallons of water. The second engine hits the hydrant and pumps water to the attack engine. If there is heavy fire, 750 gallons can run out very quick and you now have firefighters in a burning structure with no water. Not good. If civilians are trapped it's much worse. Having clear access to hydrants is critical in saving lives and property.

I agree 100% with Chris' comments about charged hoseline. It's not flexible stuff. Too tight a radius kinks it. If there are any bends or loops in the hose, you lose water pressure. Simple physics.

In reference (and agreement) with Comment #1, we'll see how good hybrids are for the environment once $7,000 batteries start piling up. But that's another topic for another day...

I also agree the picture is probably out of context given as it is on capital grounds and parking is not allowed, regardless of the hydrant location.


Kenn Fong

#22, Tom, asks a very good question. I'll remember this post from now on whenever something in Freakonomics doesn't pass the sniff test. I wonder how many other posts are tainted by slipshod or the lack of any research.

Kenn Fong
Alameda, California


A pumper truck uses a pump, people. One end sucks, the other blows. You use different hoses. When connecting the pump on the truck to the hydrant, a short, large diameter, stiff hose is used. The truck needs to be right in front of the hydrant, only a few feet away. The pump is drawing water out of the hydrant system at potentially such a high rate that the pressure in the pipe from the hydrant to the pump can sink to at or below atmospheric pressure. The suction side hose would collapse if it did not have some structural strength to it. The capacity of the pump would be limited by the pressure at the hydrant, which is not always high. The 'fire hoses' that people are thinking of are the long, thin, flexible hoses that connect to the discharge side of the pump, where the water is at high pressure.

Dubner failed to research this point in his original post. Would it be so hard to call a fire station and ask, Mr. Journalist?



I am a captain in a volunteer fire department. The comments about charged hose being less flexible are spot-on. We connect our fire engines to hydrants with hoses that are five inches in diameter, and they are virtually impossible to move when charged to pressure.

mfw13 asked about GPS in firetrucks. It's coming, but slowly. Our local government loves us, takes us seriously, and tries to get us what we ask for; but they only have so much money, and they also have to pay police officers and teachers, fix roads and schools, etc.


Preferred parking for hybrid vehicles is actually a US Green Building Council initiative as part of it's LEED certification process.


UK fire hydrants are underneath covers flush with the sidewalk - we don't have the ornamental/sticking up/iron sort used in the US.

So no parking restrictions. But perhaps our dogs aren't as happy?

I have no idea how the connection to these works or why its different...