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LADOC Committee Meeting January 28, 2020




Board of Directors Regular Meeting January 16, 2020, at 5:30 pm



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Customer Water Quality Troubleshooting

This site is intended to help customers of the San Lorenzo Valley Water District to determine the probable causes and solutions to some fairly common water quality issues.  If you are still uncertain of the cause of a water quality problem after reviewing the information below, or would rather have a staff member assist you, please call (831)338-2153.  Please note:  San Lorenzo Valley Water District staff members are water professionals and not medical experts.  If you are experiencing any symptoms of illness or discomfort, we recommend that you contact your physician immediately

Getting Started:
Here are some basic pieces of information to gather before troubleshooting water quality issues.  Alternatively, if you decide to contact the SLVWD staff to help you with troubleshooting water quality issues, this information is helpful to SLVWD staff:

  1. When did this water quality problem first start?
  2. Does this problem occur when you first turn on your water and resolves within a minute or two, or does the problem continue as the tap runs?
  3. Does this problem occur with just the cold water, the hot water, or both cold and hot?
  4. Does the problem occur at some or all inside faucets?
  5. Do you notice the same problem occurring at the outside front hose spigot?
  6. Do you have any home treatment devices, such as a water filter, or a water softener installed?  If you have a home treatment device installed, but not in use, is this device still connected to your home plumbing?
  7. Are your neighbors experiencing the same problem?
  8. Do you know what type of internal plumbing material is used inside of your home (such as copper, PEX, galvanized)?

Please read through the index below and identify the water quality problem that you are experiencing.  Each water quality problem listed in the index has a corresponding paragraph of probable causes and potential solutions. 

  • Odor
    • Determining the Source of the Odor
    • Chlorine or Chemical Odor
    • Sulfur or Rotten Egg Odor
    • Organic Solvent Odor (i.e., gasoline, turpentine)
  • Taste
  • Color or Visual Appearance of Water
    • Yellow or Brown Hot Water Upon First Draw of Faucet
    • Yellow or Brown Cold Water Running Consistently
    • Cloudy or Milky Water
    • Blue-Green Color
  • Particles/Residue
    • White or Cloudy Residue
    • White Particles
    • Brown or Orange Particles
    • Black Particles


Determining the Source of the Odor
The first step in determining the source of an odor is to see if the problem exists in the public water supply or in your home’s plumbing. 
If the source of odor is in your home’s plumbing, you will experience the odor in only one or several, but not all of the faucets in your home.  Also, if the odor goes away after running the water for a few minutes, the cause of the odor is originating somewhere in your home’s plumbing.  If your home’s plumbing is the source of the odor, you can try to flush your home’s plumbing system or you can contact a licensed plumber for assistance. 
If the odor problem is originating in the public water supply, you will notice the odor in the cold water of all of your home’s faucets and the odor does not go away after the water is left running for a few minutes.  Please contact the SLVWD at (831)338-2153 if you suspect the odor is originating from the public water supply. 
When an odor is observed in your tap water, we recommend that you perform what has been referred to as a ‘glass test’.  The purpose of the glass test is to eliminate interference from atmospheric odors off-gassing from your sink drain that can sometimes be confused with an odor from your tap water.  The procedure is as follows:

  1. Run the cold water tap for 30 seconds
  2. Obtain a clean glass, fill and dump this glass 3 times with cold water
  3. Fill the glass and turn off the faucet
  4. Take the glass of water to another room, or go outside
  5. Smell the water in the glass and determine if the odor is still present.  If the odor is still present, try to characterize the odor and compare to the odors listed below:

Chlorine or Chemical Odor:
The SLVWD uses free chlorine as a residual disinfectant throughout the water distribution system.  The concentration of the free chlorine residual in the distribution system can range from 0.5 to 1.3 mg/L (or, parts per million).  A free chlorine residual is maintained at all times in the water distribution system to ensure that the water is safe to drink.  Chlorine odors become stronger as the water temperature increases.  This can especially be noticed in the shower, or on hot days.  

Sulfur or Rotten Egg Odor
Cold Water:  If a sulfur or rotten egg odor is not noticed in the ‘glass test’, but the odor is noticed when the cold water is running down the sink drain, the odor is most likely coming from the drain.  The source of this odor is easily removed by filling the sink with hot water and pouring a couple ounces of bleach down the drain to disinfect the drain. 
Hot Water:  If a sulfur or rotten egg odor is noticed in your hot water, the most probably cause is proliferation of anaerobic bacteria.  Disinfecting the water heater may eliminate this odor.  There are resources online for the procedure to disinfect your water heater, or contact a licensed plumber.

Organic Solvent Odor (i.e., gasoline, turpentine)
If an organic solvent odor is observed in the cold water, please contact SLVWD staff immediately at (831)338-2153.  Although this is a rare problem, it is possible that your meter box was exposed to a hazardous substance.  Do not use the water as this could be a potentially serious problem. 



Over the course of the year, a change in taste of water delivered by the SLVWD can be observed.  Similar to the range of tastes observed in commercially available bottled water due to the varying minerals each brand contains, the taste of water delivered by the SLVWD also varies with its sources in operation.  The SLVWD’s source water is made up of both ground and surface water.  At different times of the year, a combination of these sources can be used at any time, depending on source availability and conditions.  A difference in taste will be noticed as the SLVWD transitions from using its various sources of water supply. 


Color or Visual Appearance of Water 

Yellow or Brown Water Upon First Draw of Faucet
Your home’s internal plumbing is the likely cause if brown or yellow water appears for only a minute or two after the tap is turned on.  This is caused by the water becoming discolored as it comes in contact with bare iron in galvanized plumbing.  The longer the water sits stagnant in the plumbing, the worse the discoloration will be.  This is why the problem is noticeable the first time the tap is turned on after not being used for a period of time.  If only a few taps show this discoloration, only a portion of your home’s internal plumbing contains galvanized pipes.  Since iron is an essential nutrient, this condition poses no health hazard.  To clear the discolored water, simply run your tap for a few minutes to clear out the discolored water and replace it with clean water from the water main or your hot water heater. 

Yellow or Brown Water Running Consistently
Occasionally, a disturbance of pipeline sediment in the water main can cause yellow to brown water which will not clear up after running your tap for one to two minutes.  The discoloration is caused by dissolved iron which is stirred up in naturally occurring sediments that exist in all water mains.  Causes of the sediment disturbance condition can include:

  • Rapid changes in water pressure due to fire hydrant use.
  • Water flow reversal in the water main due to system operations.
  • Construction activity or pipeline repair in the area.
  • Planned mainline flushing, which is designed to remove accumulated sediment.

Although the water appears discolored, this does not indicate that the water is unsafe.  Free chlorine is used as a residual disinfectant that is maintained throughout the distribution system at all times to ensure that the water is safe for cooking and drinking.  However, it is advised to avoid doing laundry until the water clears up, for aesthetic reasons.  In order to purge discolored water from your home’s plumbing, use the following procedure*:

  • Wait at least an hour before normal water use to let flow patterns re-establish themselves to baseline levels.  This will allow any sediment to settle.
  • Flush water at full velocity from your front hose spigot until it runs clear.  This should take no longer than two to three minutes.  If the water is still colored after three minutes, turn the hose spigot off, wait another hour and attempt to flush water at full velocity once again before proceeding to the next steps. 
  • Flush the inside cold water taps in your home until they flow clear.  Try to flush the faucet nearest your front hose spigot first, then move to the other cold water spigots in your home. 
  • In the event that colored water has been drawn into your hot water heater, the hot water can continue to be used until the discoloration dissipates.  This is preferred over draining and refilling your hot water heater, which may require expert help from a licensed plumber. 

*Following the procedure to purge discolored water from your home’s plumbing will generally take care of the problem.  However, depending on the conditions at the time of the colored water observation, it may be necessary to repeat the process more than once.  If the discoloration continues for more than a day, call the SLVWD staff at (831)338-2153. 

Cloudy or Milky Water
If you notice that your water sometimes comes out of the tap cloudy, or has a milky appearance, this cloudiness is caused by what is called entrained air.  Entrained air does not affect the quality of your water, it is perfectly safe to drink.  If you allow a glass of water containing entrained air to sit undisturbed for a few minutes, you will notice that the glass of water will turn clear as the bubbles rise to the top of the water and escape into the atmosphere.  Entrained air is caused by air under pressure in water pipes, similar to carbon dioxide in a bottle of soda.  When the tap is turned on, the pressure is released, which allows the entrained air to appear as tiny bubbles, similar to when a bottle of soda is opened and the soda begins to fizz. 

Blue-Green Color
Blue-green water may be due to copper plumbing corrosion, which is not a common occurrence.  If copper plumbing corrosion is occurring, the water will leave a blueish-green stain on plumbing fixtures and the water itself could have a blueish-green tint.  Copper plumbing corrosion can be caused by a home’s electrical system being grounded to the water pipes, especially if the home has a combination of pipe material installed, such as some galvanized pipe and some copper pipe without proper insulating joints installed between these two different materials. 


Particles and Residue

White or Cloudy Residue
The white or cloudy residue left on fixtures and dishes after water evaporates is made up of calcium carbonate and magnesium carbonate.  These are naturally occurring minerals that do not pose a health hazard.  These deposits can appear to have slight shades of brown, green or blue, colored by very small amounts of metals found in your water pipes.  Carbonate residue can be dissolved by soaking with white vinegar.  Deposits found on dishes after a dishwasher cycle can be minimized by using a commercially available rinse aid and not using the heated dry cycle.  The heated dry cycle can bake the carbonates onto dishes. 

White Particles
Whitish particles found in water usually originate in internal household plumbing.  The whitish particles are a combination of calcium carbonate and magnesium carbonate, known as pipe scale.  Calcium and magnesium carbonates are naturally occurring minerals and do not pose a health hazard.  Over long periods of time, these minerals deposits on the inside of internal household plumbing can flake off.  However, there are some instances that can accelerate the flaking off of scale:

  • If your home is plumbed with galvanized pipes, over time these pipes will corrode and gradually swell on the inside surface.  This swelling can cause pipe scale to flake off.  This scale can clog screens found on faucet aerators, shower heads and washing machine screens.  There is not an effective way to remove scale buildup from galvanized plumbing.  If the problem is severe, you may want to consider re-plumbing your home.
  • If your water was turned off for repair work, the pressure and velocity of water re-entering your pipes after it is turned back on can dislodge scale. 
  • If a water softener is installed, the softer water can re dissolve the pipe scale and pieces may begin to break loose.

The water heater is another source for whitish particles.  As the water is heated, calcium and magnesium carbonates precipitate out of the water, forming sand-like deposits.  Over time, these deposits can clog screens found on faucet aerators, shower heads and washing machine screens as the hot water is used.  To keep these deposits from accumulating, it is recommended to flush your hot water heater at least once per year.  Flushing your hot water heater annually can also help it to run more efficiently and extend the operating life. 

Brown or Orange Particles
Brown or orange particles are usually rust particles.  These particles can come from the inside of your home’s water pipes, or can sometimes come from the SLVWD water mains.  These particles are mostly made up of iron and are not a health hazard.  However, they can clog screen found on faucet aerators, shower heads and washing machine screens.  The physical appearance of these particles are: irregular in shape and size, can appear to be several different colors including black and feel very hard. 
Another less common source of brown or orange particles is a broken water softener.  A water softener contains many small round beads for softening water.  The screen mechanism that keeps these beads in the water softener system can fail over time and release these beads into your water.  The physical appearance of these beads is that they are similar in shape and color, feel very hard and look very similar to fish eggs.  If these water softener beads are noticed in your water, it’s recommended that you contact the installer of the water softener system for repairs. 

Black Particles
Black particles found in water typically come from one of three sources:

  • A broken water filter
  • A faucet washer or gasket that is degrading
  • A disintegrating black rubber flexible supply line hose, typically found on washing machines, hot water heaters and kitchen faucets.  Sometimes, these black rubber hoses are covered with a braided stainless steel mesh

In order to determine the source of these black particles, they first need to be characterized:

  • If the black particles are similar in shape and size, look similar to coffee grounds and are very hard, these particles are most likely granular activated carbon from the inside of an installed water filter cartridge.  Replace the filter cartridge, or contact the manufacturer of the filter for further assistance. 
  • If the black particles are solid, but have a ‘rubbery’ feel to them and only appear at one faucet, they are most likely pieces of a degrading faucet washer or gasket.  To solve this issue, replace the faucet washers.
  • If the black particles can be smeared easily between two fingers, they are probably from the inside of a rubber flexible supply line hose.  Over time, the free chlorine in the water causes the rubber to break down.  To solve this problem, replace the hose with a hose that has a liner that is identified as chemical or chlorine resistant.  Typically, these rubber hoses have a one to five year warranty. Save Our Water Logo smart garden logo

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