Frequently Asked Questions

FAQ Regarding Water Hardness

For water quality data for non-regulated parameters, such as pH, alkalinity, hardness, and conductivity, are provided on SPU's website at:


                      How do we know High-Density Polyethylene Pipe (HDPE) is safe to use for Drinking Water?

What is HDPE pipe?

High-Density Polyethylene or HDPE pipe is a commonly produced, flexible plastic pipe made of thermoplastic high-density polyethylene widely used for low-temperature fluid and gas transfer. The strong molecular bond of HDPE pipe materials helps it to be used for high-pressure pipelines. HDPE plastic is one of the most versatile of plastics—used in everything from hard hats to house wraps—it's also widely recycled, in both its rigid form (e.g., containers), and flexible form (e.g., polybags). Polyethylene pipes have a long and distinguished service history for gas, oil, mining, water, and other industries. Due to the low weight and high corrosion resistance of HDPE pipes, the industry is growing tremendously.

What is HDPE made from?

HDPE pipes are made by the polymerization of ethylene, a by-product of oil. Various additives (stabilizers, fillers, plasticizers, softeners, lubricants, colorants, flame retardants, blowing agents, crosslinking agents, ultraviolet degradable additives, etc.) are added to produce the final HDPE pipe and components.

What is the history of HDPE pipe use?

In the year 1953, Karl Ziegler and Erhard Holzkamp discovered high-density polyethylene (HDPE). Solid-wall HDPE pipes began replacing metal pipes in oil and gas systems in the late 1950s. In the early 1960s, gas utilities started replacing failing iron pipes with HDPE pipes, and because of its success, 95% of all new gas distribution systems installed today use HDPE. Soon after, HDPE pipes began to be used in agricultural drainage systems. In the 1980s, HDPE began to replace metal and concrete in stormwater culverts. HDPE is the insulation coating on the overhead telephone and electrical lines. HDPE is the same substance used in bottle caps, reusable water bottles, plastic lumber, patio furniture, hula hoops…the list goes on and on.

Is HDPE pipe considered “Food Safe”?

HDPE pipe is a common industrial plastic that is highly utilized in modern applications. Federal Regulation oversees the use and service of HDPE. The FDA considers HDPE pipe to be “approved food grade - BPA Free” (aka ANSI/NSI 61) and is approved for potable water applications. The molecules of HDPE are more tightly packed and stable than other food-grade plastics, meaning less plastic can leach into your food. The safest food-grade containers/buckets made from HDPE have the #2 symbol stamped on them, which indicates the plastic is considered safe from any BPA leakage. There has been no evidence of any widespread health problems associated with the use of HDPE in food and beverage or drinking water applications.

Will Sunlight affect HDPE pipe?

Sunlight contains ultraviolet rays that reduce the tensile properties of plastics with time. Usually, 3-5% carbon black is added to HDPE to make it UV resistant, which turns HDPE pipes black in color. HDPE pipe is installed in the ground, covered with at least 18” of ground cover, and not subjected to UV rays. This UV protection allows HDPE to be used in telephone and electrical wires that are consistently exposed to UV light, without any loss of tensile strength.

Will gasoline or wildfire affect HDPE pipes?

Gasoline does not adversely affect HDPE. The material does not soften or lose strength when exposed to gasoline. However, HDPE pipes will burn if exposed to an outside fuel source (i.e., gasoline). This could happen if there was a large fuel spill adjacent to the pipe. However, the fire would extinguish itself quickly due to the lack of an air supply and the fact that the pipe is buried.

Why did we choose HDPE pipe?

• The durability of HDPE is one of the benefits of HDPE. It has 100+ years of useful life.

• HDPE saves money because it is inexpensive compared to ductile iron pipe or copper. Currently, HDPE is less than half the cost of Ductile Iron Pipe.

• HDPE is superior to metals. It is lighter, flexible, and doesn’t fracture due to freezing.

• HDPE is efficient to produce. It requires less energy to fabricate, transport, and install than metal alternatives.

• HDPE won’t rust or fracture. It is resistant to corrosion and scaling.

• HDPE is rigid enough to hold its form over time, even in a seismically active area, and it is flexible enough to bend around corners and under creeks or streams.

• Installation of HDPE pipe is often “trenchless,” meaning that the new pipe can be pulled through the old pipe, and the road does not have to be “open cut.”

• 20-foot sections are joined using butt fusion, making a longer section of pipe that is effectively seamless.

• The seamless HDPE pipe is essentially leakproof and has a longer life than ductile iron pipe because there are no joints to slip or allow root intrusion.

• HDPE is better for our employees, too. It’s so light, one person can carry a 20- foot section, and it won’t break or hurt someone’s foot if it’s dropped!

• Using flexible HDPE typically means no ugly trenches or damaged driveways, streets, sidewalks, or landscaping. 

• Best of all, replacing old mains with HDPE saves you money! The design, purchase, and installation of HDPE are significantly more affordable than Ductile-Iron pipes. This means your water rates go further.

What about microplastics? Will using HDPE pipe cause me to be exposed to microplastics in my drinking water?

Microplastics are plastic pieces between one micrometer (one-millionth of a meter) and five millimeters in size. Nanoplastics are even smaller than one micrometer. 35% of all microplastics come from synthetic fibers (i.e., fleece) released during clothes-washing. Another 30% comes from car tires. Plastic breaks down over time, especially when exposed to the atmosphere and UV light for long periods of time. HDPE pipe is protected from breakdown by the black carbon that blocks UV light and the fact that the pipe is buried and not exposed to the atmosphere.

Wait, I have heard about plastic pipes before, don’t they break easily?

The polyvinyl Chloride (PVC) pipe material introduced in the 1970s led to an unacceptable leakage rate. This type of pipe was prone to splitting and is not the same as the HDPE plastic pipe we use today.

Is there a situation where HDPE pipe is not a good choice?

HDPE pipes can work satisfactorily in a wide temperature range of -220 F to +180 F. However, the use of HDPE Pipes is not suggested when the fluid temperature exceeds 122 F (50 C).

Would you like more information on Trenchless Installation of HDPE?

Check out these videos:

Information for this FAQ has been collected from these resources:


The Plastics Paradox, Facts for a Brighter Future, Chris DeArmitt, PHD


How do I start a new service?

To start a new service, you have three options:

  1. Complete our online form
  2. Email us at
  3. Call the District office at 425-255-9600

We prefer to have the online form filled out so we have your complete information and correct spellings and will set up your account based on the information you provide.

Regarding Current Lead Issue

What is the Pink Residue in my Bathroom?

Please click to open the form

Each year, a few Water District No. 90 customers call to ask about a slimy pink substance that sometimes forms in moist areas around their homes. They most frequently observe it in toilet bowls, on the surfaces in shower stalls, bathtub enclosures, in sinks, and in pet water dishes.

Red or pink-pigmented bacteria known as Serratia marcescens is thought to be the cause of the pink stuff. Serratia bacteria are common inhabitants of our environment and can be found in many places, including human and animal feces, dust, soil, and in surface water. The bacteria will grow in any moist location where phosphorous containing-materials or fatty substances accumulate. Sources of these substances include soap residues in bathing areas, feces in toilets, and soap and food residues in pet water dishes. Serratia can also grow in tap water in locations such as toilets in guest bathrooms where the water is left standing long enough for the chlorine residual disinfectant to dissipate. Serratia marsescens is not known to cause any waterborne diseases.

Once established, the organism usually cannot be eliminated. However, periodic and thorough cleaning of the surfaces where the pink slime occurs, followed by disinfection with chlorine bleach appear to be the best way to control it. Scrub the surfaces where phosphorus and fatty substances, or the bacteria accumulate with a brush and a household cleanser. Then disinfect the surfaces where the slime has formed with a strong chlorine bleach solution. Leave the disinfectant solution on the affected surfaces(s) for 10-20 minutes before thoroughly rinsing it away with clean water.

To control “pink stuff” in toilets, clean the bowl thoroughly and spray chlorine bleach into the bowl and under the bowl rim. Also, add ¼ cup of bleach to the toilet tank. Let the bleach stand for 15-20 minutes. After 15-20 minutes, flush the toilet a couple of times to rinse the disinfectant out of the tank and the bowl.


Bleach should not be left in the toilet tank for prolonged periods; it will damage the rubber valves and seals inside. Whenever a pink film starts to reappear, repeat the cleaning and disinfection process.

If you have further questions, contact our office at 425-255-9600 or email

FAQ Boil Order

How do I contact the District?


15606 S.E. 128th Street
Renton, Washington 98059

Office Hours:

Monday through Thursday, 8:00 A.M. to 4:30 P.M.

Friday available by phone or email 8 AM to 4:30 PM. Office closed for walk-in.

Phone Number: (425) 255-9600

Fax Number: (425) 277-4128

Email: info@KCWD90.COM

How can I turn off the water in an emergency?

All homes should have a shut-off valve located at the residence. However, if your home does not have one, you may (in an emergency), turn the water off at the water meter. Meters are generally located at the front of the property, near the road. The recommended tools to have on hand are a crescent wrench and/or a meter wrench which can be purchased at your local hardware store (approximately $15.00). Firstly, locate the valve (silver dollar-sized, brass-colored with a raised bar in the center). Place the wrench over the raised bar and turn it to the right until the “eyes” on the valve are aligned. Repair leak(s) and reverse the process to re-establish water service to the residence.

Can I turn my water back on myself?

Meters are maintained by the District, but in emergency situations, it is advantageous that the homeowner turn the water on/off. When turning the water back on, reverse the steps in the "How can I turn my water off in an emergency?" FAQ section. Turn the raised bar only ¼ turn counter-clockwise to bring the water back into the system slowly. Then open the valve all the way.

Can my water be shut off in a District emergency and will I be notified?

Yes. In the event that there is a planned shut down, the affected customers will be notified prior to the shut down. For customer convenience, our field crew will leave a door tag with the date and estimated down time. However, in the event of such a shutdown, customers should make sure that they do not operate dishwashers, washing machines and showers during the shut down period. However, there may be critical circumstances which would result in an unplanned shut down (e.g., an accident, main break, etc.). In this situation, there would be no notification to our customers. The main focus would be to repair and/or restore water service as quickly as possible with a minimum impact to our affected customers. Please note that customers can call our main phone number 24-hours-a-day for information and/or to report an emergency.

Does the water contain Fluoride?

Yes. The range of fluoride for all of the District’s water sources is between 0.8 and 1.2 parts per million (ppm). The average is 0.8 ppm. The EPA’s maximum allowable limit is 4.0 ppm.

How do I know the District's water is safe?

The District is committed to providing residents with a safe and reliable supply of high quality drinking water. SPU and private laboratories tests our water regularly using sophisticated equipment and state of the art procedures. We are proud to report that the water provided by the District meets or exceeds established State and Federal standards for appearance, safety and water-quality standards. Each spring the District sends a “Water Quality Report” to every customer. The report details the District’s water quality analysis for the previous year. It also includes additional health information, information for sensitive people, and a detailed list and quantity of all detected compounds.

What do I do if I own a RENTAL PROPERTY in the District?

If you are the owner of a rental, you must have an “Owner Account”. You will need to call the office and we will set one up for you. You will start receiving a duplicate copy of the renter’s bill, which allows you to know if your renter is making their payments.

When you know the date your renter is moving in or out, notify us immediately. We will schedule a meter read to close their account.  This can be done online under the Customer tab and "Start/Stop Service".  You will fill out the "Close an Account" form.

The District's fee is $25.00 to close an account. This fee is to cover field and office expenses involved to close an account.

Please note: We allow 30 days for the renter to pay the final bill before we transfer the balance onto an Owner Account if the balance remains unpaid.

You may call us to verify that the renter paid their final bill before you give back their deposit.  You may also request a final bill prior to giving back their deposit.

Please be advised, unlike any other utilities, Washington State Law requires that the “water service stay with the property” (ref. RCW 57.08.081). This means, if a renter vacates your rental property with an unpaid balance, after 30 days the Owner is ultimately responsible for the water bill.

What should I do if I leave the area for the winter, go on vacation or a temporary job assignment?

If you are planning to be away for an extended period of time, contact the District office to have the water shut off at the meter.

Inside your home, you should, shut off your hot water heater (at the circuit breaker) and open a hot and cold water faucet in the house and one outside faucet to drain the water system and leave faucets open.

To protect outside faucets from freezing, cover them with some type of insulation.

Make sure to let us know if you will be gone for over four (4) months so we can note your account and in some cases, we can put your account under a “non-use” rate. In that situation, we would need to have specific departure and return dates.

When you return, shut off all faucets and turn on the water at the meter. Open faucets one at a time to remove any air in the line. Turn the water back on in the house and check for any leaks by watching the water meter for movement.

What should I do if I plan to move?

If you are a homeowner or a tenant the procedure is the same. Simply go to the "Customer" tab, "Start/Stop Service" and fill out the appropriate form. We will need to know the closing date; new owner/tenant name (if known); and forwarding address information. If you are selling your home and going through escrow, the Escrow Company will usually fax a final bill request to our office. We encourage both the previous and new owner/tenant to call us.

When and where are the Board meetings?

The regularly-scheduled Board meetings are held on the first and third Tuesday of each month, commencing at 4:30 p.m. The public is encouraged to attend. If you have item(s) and/or concerns you would like included on the agenda, please contact the office during normal business hours. Your request must be received at least 48 hours prior to meeting dates.

Where does our drinking water come from?

The District purchases approximately 70% of its water from Seattle Public Utilities (SPU). SPU draws its water from the Cedar and Tolt rivers. Additionally, 30% of our water is produced from our own well. The water you normally consume from KCWD 90 comes from the Cedar River and our well.

What if I have a complaint?

Any complaints or concerns should be directed to our District staff who will work with you in resolving your complaint and/or concerns. Unresolved complaints can be taken to the Board of Commissioners.