Join Moulton Niguel and the EPA to fix leaks!

Did you know that one leaky toilet can cause your water bill to increase by more than $500?

According to the U.S. Environmental Protection Agency, household leaks can waste more than 1 trillion gallons of water annually nationwide. Common types of leaks found in the home are worn toilet flappers, dripping faucets, irrigation systems, and leaking pipes including a home’s main water service line. While these types of leaks can often be repaired by homeowners, they can go unnoticed and waste thousands of gallons of water per month. This guide will help you identify common plumbing leaks and provide steps to troubleshoot and make repairs yourself.

Customers can request a leaky toilet test any time of the year by calling (949) 831-2500 or emailing Need some help on how to perform the dye tab test? Watch the video tutorial below. 

You can view you water use with our free customer portal,, which can be accessed online through your PC or tablet, or on your phone by downloading the MyWaterMNWD app.

Once in the portal, you can navigate to the Usage section to view your monthly, daily, and hourly water use. If you have received a leak alert, look at the daily and hourly use views to see when the continuous use started. Use some of the troubleshooting tips below to see if you might have a leak.

  1. Household usage review – Each person in a household is budgeted/allocated 55 gallons per person per day. View your household’s daily water use and compare your usage to the budgeted amount.
  2. Leak detection – Use the “Usage” menu to view the “Daily” and “Hourly” charts. Modify your water usage chart by selecting a recent date range when no one was at home. If water use occurred on that date and time selected, you may have a leak or you may have accidentally left water on. Under normal circumstances, a household will not have 24 hours of usage. If 24-hour usage is determined, you may have a potential leak.
  3. Landscape and Irrigation Water Usage: Customers that have an automatic irrigation system, will have high water usage during the time of day the irrigation is on. View your daily water use chart to determine how much water is used for landscape irrigation by comparing your watering days to your non-watering days.

The most frequent type of leak at a residential property is a toilet leak. There are some inexpensive and easy tests to diagnose a toilet let. See the section on “Toilets” below to read more and access our helpful “Potty Talk” leak troubleshooting video series.

Other common household leaks include irrigation leaks, such as stuck valves, and service line leaks. We have created two sections dedicated to those leak types below.

If you’ve already ruled out the most common sources of water leaks, but still cannot identify the source of continuous water use, see if one or more of these conditions apply to your home?

  • Did you need to jiggle the handle on a toilet recently? Or has the handle been stuck?
  • Was a hose or sprinkler accidentally left on?
  • Does your pool, spa, or pond have an autofill? Could it possibly be stuck open?
  • Do you have a young adult or night owl living with you that could cause water use each hour?
  • Did someone’s schedule change? Or, has someone started working from home?

If none of these apply, you may want to consider contacting a licensed professional for further investigation of your plumbing and/or irrigation systems.

If you need help looking for water-efficient devices at your local retail stores, we encourage you to look for the Environmental Protection Agency (EPA)’s WaterSense logo. Any products that have an EPA WaterSense tag are water-efficient, and according to the EPA, are “certified to use at least 20% less water.” WaterSense makes it easy to find and select water-efficient products that can help reduce your water use, which can also benefit your water bill and the environment.

Some of these products include showerheads, irrigation controllers, toilets, showerheads and many more! And an added bonus? Moulton Niguel offers rebates on several water-efficient devices including toilets, washing machines, irrigation controllers, sprinkler nozzles and much more. Visit our website to see all of the current rebates for Moulton Niguel’s residential and commercial customers at:

If you identified a leak at your home, consider using the following isolation method to find the location of the leak. This process assumes that you have a house shutoff valve and/or an irrigation shutoff valve that can be opened and closed to help you rule out locations that could be leaking.

Before beginning this process, make sure to shut off all of the water using appliances in and around your house, so their operation does not affect the isolation test. The following website provides visuals and step and step instructions to complete the isolation process: Smart Home Water

A note of caution: If your shutoff valves are old and corroded, they may fail or break during the isolation exercise. If you have concerns about turning plumbing and irrigation valves, you may want to consider contacting a licensed professional for support.

  • Start from the wall where the water pipe enters the house. Follow the pipe away from the wall past a bell-shaped pressure regulator. Keep following the pipe away from the wall, and there should be the HOUSE SHUTOFF VALVE. Even further from the wall there should be a tee or a right-angle pipe coming out from the main pipe. On that pipe, there should be the IRRIGATION SHUTOFF VALVE – it might be plastic or metal.
  • Turn off both the house shutoff valve and the irrigation shutoff valve. Then check your meter. If the water is still flowing, check if you see soggy or super green spots in your lawn, or if you see wet or weeping on your sidewalk. This may indicate a potential leak in the pipe that runs from the meter to the house (service line).
  • If there is no flow showing when both the house shutoff valve and the irrigation shutoff valve are closed, you can conclude it’s not likely to be the service line.
  • urn on the irrigation shutoff valve and recheck the meter. If the meter shows flow, this may indicate a potential leak in the irrigation system.
  • If it’s not the service line or the irrigation system, turn on the house shutoff valve and recheck the meter. If the meter shows flow, this may indicate a potential leak in the house.
  • If you don’t have an irrigation shutoff, you can look for some of the common breaks we see in irrigation:
    Leaky irrigation valve body
    Leaky solenoids (the part where wires come out of the top of the valve)
    Broken sprinkler heads
    Broken lateral lines, the pipes that connect the valve to the sprinklers.

Repairing a leaky toilet can save up to 500 gallons of water a day! Making the toilet the number one cause of a high-water bill.

In many cases, a toilet leak can be silent and go unnoticed unless you do routine maintenance. Get started looking for toilet leaks by lifting the lid on the toilet tank and listening for water movement and looking for signs that the water level is changing. This could be a slow process because many leaks start small and grow over time. Also verify that the water level is not too high and flowing into the overflow tube.

Listed immediately below are common issues found in toilets along with video resources to guide you through finding and fixing common toilet leaks.

  1. Leaking Flapper: A misaligned or warped flapper that is not creating a seal between the toilet tank and bowl is the most common toilet leak. Drop a toilet dye strip in the toilet tank so that it will turn the water blue. Wait 15 minutes (Do NOT flush your toilet!) and check for dye in the toilet bowl. If the water in the toilet bowl turns blue, then the flapper is not creating a seal between the tank and the bowl. Fortunately, replacement flappers can be purchased at home improvement stores for usually $15 or less. We have an instructional video that shows you how to replace them yourself.
  2. Leaking Fill Valve: The porcelain tank lid can mask the sound of a slowly running fill valve, so lift the tank lid and look and listen for water movement.  Check the adjustment screw on the fill valve to ensure optimum water level at ¾” below the top of the overflow tube.
  3. Loose Handle: If the toilet handle feels loose, the nut inside the tank might be loose and or broken.
  4. Running Toilet: Jiggling the handle? If so, the chain, flush lever, or handle could be sticking and causing the toilet to run.

For further assistance, check out our “Potty Talk” video series that was created to help you find and fix toilet leaks:

Video #101: Basic Toilet Parts 

Video #201: Parts of the toilet that commonly cause leaks

Video #301: Learn how to diagnose toilet leaks

Video #401: Learn how to replace leaky flappers and broken fill valves

Watering before sunrise and after sunset is a recommended practice to prevent water waste from wind and evaporation, but it also means irrigation leaks can go unnoticed unless performing routine maintenance.

Continuous water use from an outdoor leak may occur because of a stuck irrigation valve or from a leak in the joint or irrigation line leading to the irrigation valve assembly.

Other types of irrigation leaks only occur when your irrigation system is running. This won’t trigger a leak alert, but it could lead to a high bill. Make it a routine to check for leaks in the following: irrigation valves, connection points and joints, and sprinkler heads or drip irrigation lines.

Routinely run an irrigation test of the system and look for missing sprinklers, small geysers, misdirected spray, low pressure causing sprinkler heads to not pop up fully, drip lines that have been cut or moved out of place. This is the fastest way to find broken or missing sprinklers, or ruptured irrigation lines.

Your water service line or “supply pipe” is located underground connecting the water meter to your house water supply (see image below).

To evaluate a service line for a potential leak, use the following procedure:

Close the house valve and all other valves that stem from the service line. This could include a main irrigation valve, multiple irrigation valves at the valve assembly, and/or a pool fill valve. Check your water meter for movement (Note: your meter is likely located near the curb at the front of your property).

If the meter is moving, this could indicate a service line leak. A leaking service line can cause standing or ponding of water on the surface above the line.

If you’re planning to perform a repair at your home, keep the following in mind:

  • The District has several video resources to support you (see below).
  • Look up model numbers and serial numbers before heading to your local hardware store to look for the defective items.
  • Turn off your house valve when working on indoor plumbing.
  • Contact the District if you need to make a repair to your irrigation valve or service line.

If you would like professional assistance to repair your plumbing or irrigation leak, you can try the following resources:

Licensed plumbers:  Click Find My Licensed Contractor.
Irrigation specialists: Click Consumer Resources, then click Find My Contractor.

Video Resources:

Potty Talk 101 – Overview of basic toilet parts 

Potty Talk 201 – Identifying the toilet parts that create leaks  

Potty Talk 301 – Learn how to diagnose toilet leaks

Potty Talk 401 – Learn how to replace leaky flappers and running fill valves 

Learn how to replace leaky faucet aerator 

Learn how to replace leaky showerhead 

Customers who repair leaks in a timely manner and return to using water efficiently (within their customized water budget) may request a bill adjustment for one high bill.

Bill adjustment request forms must be submitted within 30 days of your high bill.  It is the responsibility of the customer to contact the Billing Department to make any payment arrangements if payment cannot be made in full at the time payment is due. Any approved bill adjustment will be issued as a credit on a future water bill.

For more information about the District’s Bill Adjustment process and to submit a request form, visit

Understanding your water service to effectively troubleshoot issues

With so many pipes bringing water to your home, it may be difficult to identify where the responsibility of a leak may lie. We are here to help clarify and distinguish who is responsible for the maintenance and repair of pipes and leaks. We also would like to provide education and information so you are able to troubleshoot any issues you may experience.

The image below depicts the responsibility between Moulton Niguel Water District and each customer. *Please note the situation may look slightly different depending on the meters.

Moulton Niguel Water District’s Responsibility – Moulton Niguel is responsible for the pipes that bring water from the water main located under the street, all the way to the meter outlet coupling. This includes:

  • Connection to the water main in the street
  • Service line from the main to the inlet side shutoff valve (curb stop or angle stop)
  • The water meter, water meter box and the outlet side coupling

Customer Responsibility – Customers are responsible for everything from the connection of their service line to Moulton Niguel’s coupling. This includes but is not limited to: 

  • Customer’s service line from the meter to the house
  • House valve
  • All plumbing fixtures both inside and outside the house

Still have questions? Visit our Leak FAQ’s.