How many gallons is 1 drip per second?

A leaky faucet that drips 1 time per second can waste a significant amount of water over time. But how much exactly? Let’s take a look at some estimates to understand the gallon equivalents of 1 drip per second.

Quick Estimates

As a quick estimate, 1 drip per second is approximately:

  • 9-10 gallons per day
  • 300 gallons per month
  • 3,600 gallons per year

So if you have a faucet that’s leaking at a rate of 1 drip per second, it could potentially waste thousands of gallons of water annually. Stopping even a minor leak can lead to substantial water savings over time.

Calculating Gallons in a Drip

To get a more precise measurement, we need to calculate the volume of a single drip. The volume of a drip will depend on the type and size of the faucet or nozzle.

As an example, let’s assume the drip is coming from a standard household bathroom faucet with a 4 millimeter (0.16 inch) nozzle opening. Based on research into drip flow rates, each drip from a 4mm nozzle is approximately 0.05 milliliters (ml) or 0.0017 fluid ounces (fl oz).

Knowing this, we can now calculate gallons as follows:

  • 1 liter = 1,000 ml
  • 1 gallon = 3,785 ml
  • 1 drip (0.05 ml) = 0.0000132 gallons

So a single 4mm drip is about 0.0000132 gallons.

Drips Per Second to Gallons Per Unit of Time

Now we can use the single drip volume to estimate gallons wasted over various time units for a leak rate of 1 drip per second:

  • Per minute:
    • 1 drip = 0.0000132 gallons
    • 60 drips (1 per second) = 0.00792 gallons
  • Per hour:
    • 60 minutes * 0.00792 gallons per minute = 0.4752 gallons
  • Per day:
    • 24 hours * 0.4752 gallons per hour = 11.4 gallons
  • Per month:
    • 11.4 gallons * 30 days = 342 gallons
  • Per year:
    • 11.4 gallons * 365 days = 4,161 gallons

So based on a 4mm drip size, 1 drip per second would waste about 11 gallons per day, 342 gallons per month, and 4,161 gallons per year.

Factors That Impact Drip Volume

It’s important to note that the actual volume will vary based on factors like:

  • Drip speed – Faster drips are often larger
  • Water pressure
  • Water temperature
  • Faucet/nozzle size – Larger openings release bigger drops
  • Mineral deposits – Can restrict water flow
  • Water viscosity – Thicker liquids form larger drops

So while the 4mm drip example gives us a good ballpark estimate, your specific leak volumes could be higher or lower in reality.

Verifying With a Measured Test

To get the most accurate measurement for your specific situation, you can conduct a simple self-test:

  1. Place a measuring cup under the dripping faucet and allow it to drip for a set period of time such as 10 minutes.
  2. Measure and record the amount of water collected.
  3. Convert the amount to gallons (1 gallon = 3,785 ml).
  4. Divide gallons by the number of minutes to get gallons per minute.
  5. Multiply gallons per minute by 60 to estimate gallons per hour.

This measured test will give you the confirmed drip rate for your faucet’s condition, flow rate, water pressure and other factors.

An Example Measured Test

Here is an example measured test:

  • Placed measuring cup under leaky faucet for 10 minutes
  • After 10 minutes, cup contained 45 ml of water
  • 45 ml = 0.0119 gallons (45 ml divided by 3,785 ml per gallon)
  • 0.0119 gallons per 10 minutes = 0.00119 gallons per minute
  • 0.00119 gpm multiplied by 60 minutes per hour = 0.0714 gallons per hour

So for this specific leaky faucet, the measured drip rate was approximately 0.07 gallons wasted per hour.

Measuring Over Time for Ongoing Leaks

For a leaky faucet that keeps dripping non-stop, you may want to measure the wasted water over a longer period of time such as hours or days.

To do this:

  1. Place a large bucket or other container under the leak.
  2. Mark the starting water level.
  3. Allow the faucet to keep leaking into the container for the time period you want to measure (such as 24 hours).
  4. After time has elapsed, mark ending water level.
  5. Measure the change in water volume.
  6. Convert to gallons.
  7. Divide gallons by number of hours to get hourly rate.

This will give you the average dripping rate over a longer term for an ongoing leak.

Factors That Increase Dripping Rate Over Time

For leaks that persist for weeks or months, the dripping rate often increases over time as the leak worsens. This can be caused by factors like:

  • Mineral deposits enlarging dripping opening
  • Water pressure eroding the faucet opening
  • Freezing/thawing cycles damaging the faucet
  • Corrosion from dripping water exposure

So leakage from an existing drip may not be constant, and can intensify over time leading to higher water waste. Periodically remeasuring the drip rate is advised.

Conversion Table: Drips to Gallons

Based on the typical drip size from a 4mm nozzle opening, the conversion from drips to gallons is:

Time Drips (at 1 drip/second) Gallons
1 minute 60 drips 0.00792
1 hour 3,600 drips 0.4752
1 day 86,400 drips 11.4
1 month 2,592,000 drips 342
1 year 31,536,000 drips 4,161

This table can provide a quick reference for estimating total gallons wasted for a given number of drips over time. Keep in mind your specific dripping rate could vary.

Financial Cost of Leaked Water

In addition to wasting water, leaks can also cost money on your utility bills. To estimate the financial cost of a leak:

  1. Calculate gallons wasted per day/month/year
  2. Determine water rate charged by your utility company (e.g. $5 per 1,000 gallons)
  3. Divide gallons leaked by 1,000
  4. Multiply gallons in thousands by water rate

Using the 11 gallons-per-day estimate for 1 drip/second:

  • 11 gallons per day
  • Water rate = $5 per 1,000 gallons
  • 11/1000 = 0.011 thousand gallons
  • 0.011 * $5 = $0.055 lost per day

So the estimated daily cost of a 1 drip/second leak could be around 5 cents depending on local water rates. Over a year, this could add up to around $20 in wasted water costs.

Importance of Fixing Leaks

While a single drip may seem minor, the gallons wasted and costs incurred really add up over time. Even small leaks should be repaired promptly both to conserve water as an essential resource, and to avoid unnecessary charges on your utility bills.

Many leaks can be fixed quickly and easily with basic plumbing repairs. Replacing worn washers, gaskets, pipes, and fixtures can eliminate wasteful drips and restore full water shut-off. Having leaks fixed by a skilled plumber as soon as they start dripping can prevent the problem from worsening over time.

Installing advanced washers, aerators, and other high-efficiency fixtures when repairing or replacing can also help reduce ongoing water waste and drips in the future.

Be vigilant in listening and looking for any small drips or weeping around faucets, showerheads, toilet valves, pipes, and connections. Catching and fixing drips promptly will have meaningful benefits for water conservation and your budget.


A minor-seeming drip of 1 drop per second from a faucet can in fact waste thousands of gallons of water over months and years. By understanding drip flow rates and conversions to gallons, you can better estimate the potential water loss and cost from small leaks.

Measuring your specific drip rate, fixing drips quickly, and choosing efficient fixtures are all important in preventing wasted water and money over time. Be attentive and proactive in leak detection and repair to maximize conservation of our essential water supplies.

Leave a Comment