Wastewater Questions and Answers

Sewer Service Questions

How do I find out where my sewer line is located and where I am tapped into the city main?

The City and County of Denver is only responsible for main public sewers. For information about your private tap/service line, we recommend you to hire a licensed plumbing company that provides such services.

Who do I call if I have a sewer back-up?

Immediately phone (303) 446-3400 and report the problem. A maintenance crew will be dispatched to your location as quickly as possible.  If the problem is found in the city sewer line, Wastewater personnel will service the line and correct the problem. If cleanup is necessary due to a problem in the city line, we will arrange to have it completed in an efficient manner. If the problem is found to be your private line rather than the city sewer line, we will inform you as soon as possible. It would then be your responsibility to contact a plumber to service your line and repair any damage which may have occurred.

We keep getting a foul sewer odor in our home. Why is this happening?

Believe it or not, a dry drain can lead to this condition. Drain pipes are constructed to hold a small amount of water. This retained water creates a seal to keep odors from coming up into your house. This water seal can evaporate, thus allowing foul odors to come into your house. To remedy this situation, you should pour a little water down your drain each month.

What should I NEVER flush down the toilet or pour down the drain?

Do NOT flush disposable diapers, baby wipes or feminine hygiene products as they will clog your sewer line. In addition, never pour grease or gummy substances down garbage disposals, toilets, or floor drains. Flammable liquids, i.e. oil, gasoline, paint thinner, etc., should never be poured into your sewer line as they can cause a fire hazard or create a harmful coating on your sewer pipe. Never flush plastic tampon containers, pencils, pins, hypodermic needles, broken glass or other foreign objects that can lodge in your sanitary line and prevent consistent flow.

For more information visit the Stormwater Quality page.

Why do roots grow into my sewer line?

The combination of moisture, warmth, and nutrients that exist in all sewer lines (private and city) provides an excellent environment for roots to grow. Roots from trees, plants, and shrubbery are first attracted to the exterior of the sewer line and will penetrate the smallest crack or pin hole. This growth can eventually clog sewer lines.

If our drinking water has a foul taste does that mean sewer water is getting into it?

It is extremely unlikely that sewer water will get into your drinking water. Incoming drinking water lines are designed to be pressurized and are installed above outgoing sewer lines. With this design, any sewer leakage would run downward and away from the line providing you with drinking water.

If you have a question about your water service, call the Denver Water Department at (303) 893-2444.

General Questions

What is the Wastewater Management Division?

The Wastewater Management Division, which is part of the Department of Transportation and Infrastructure, builds, operates and maintains Denver's sanitary sewer system and storm drainage system. We maintain more than 1,525 miles of sanitary sewers and 793 miles of storm drainage facilities.

Why do I receive two bills from Wastewater?

One bill is for sanitary sewer charges. This is prepared monthly, and is combined with your water bill.

You will also receive another bill for storm drainage. This is calculated annually but billed semi-annually. Storm drainage bills are sent to every owner of improved property within Denver.

What's the difference between storm drainage and sanitary sewer charges?

Sanitary sewer charges are for the collection, treatment, and disposal of water going down your sinks, drains, and toilets. Storm drainage charges are for the collection and disposal of rain water and snow melt. The City's sanitary sewers and storm drainage facilities are two completely independent systems.

Can I use graywater?

Yes; in May of 2016, Denver City Council passed an ordinance to allow graywater use.

Learn more about uses and design requirements at denvergov.org/graywater

What should I do about drainage complaints in my neighborhood?

The best course of action to report a drainage problem is to call 3-1-1 and report the specific type of problem (i.e. ponding, flooding, icing, illicit discharge, broken inlet, blown manhole cover, etc.) and the location to the 3-1-1 operator who can best facilitate the request to the appropriate department for response.

Why are there more drainage problems after rainfall?

Denver streets are a critical and necessary part of the storm drainage network. During large rain storms, the streets work together with the underground pipes to carry stormwater to the creeks and gulches. Denver standards allow for surface flows in excess of the pipe capacity to be carried by the streets at one-foot of depth or less during heavy rain storms. Streets that experience more than one foot of depth likely need a larger underground system than what currently exists. Identification of these undersized neighborhood pipe systems can be found in the Denver Storm Drainage Master Plan.

Many of the older systems in Denver were not constructed to handle the type of density and amount of imperviousness that is seen today. The average age of Denver’s storm drains is 39 years, with some of the oldest pipes 90 years old or more. As more land is developed in these areas, the increase in water runoff from added impervious surfaces can overwhelm the capacity of the older systems. In the newer parts of town (i.e. Green Valley Ranch, Central Park), the systems were constructed with a higher level of service that meets today’s industry standard.

How are storm drains cleaned?

DOTI's Wastewater Management Division Systems Maintenance cleans storm drains on a regular basis. There are tens of thousands of storm drain inlets citywide, so not every drain is cleaned after every storm. 

Several hundred storm drains in Denver are siphons. Unlike a storm drain that carries flow to a river or gulch, a siphon merely conveys flow from one side of the street to the other where it bubbles up and continues flowing down the gutter. As shown in the diagram below, the water flows well during storms to get under the street and bubble back out on the other side. However, after storms whatever water is left in them sits and can get stagnant and start to smell.

DOTI crews clean siphons on a regular basis in the spring, summer and fall and also use an EPA-approved larvacide tablet which lasts up to 30 days to kill mosquito larvae. Sometimes siphons get stinky between cleaning, especially during dry spells due to grass clippings, leaves, other organic matter which fall or are placed in the street and then wash into the siphon where they become trapped and start to decay. When this occurs the siphons need to be cleaned more frequently. In such cases, our Systems Maintenance staff can be dispatched to the site when we receive a report.

Help the functionality and maintenance of Denver's storm drains:

  • Sweep gutters in front of homes of trash and debris
  • Bagging lawn clippings
  • Don't blow leaves or other loose debris onto the right-of-way
  • Clear debris from inlets after storms
  • Secure trash bins in areas where they won’t float away
  • Don't set out trash bins for morning pickup the evening before in summer months

Sanitary Sewer/Storm Drainage Billing Questions

Why am I billed for storm drainage?

When land is undeveloped, rain and melting snow will soak into the land or naturally flow to streams and rivers. When land is developed, an impervious surface is created. An impervious surface is a man-made area that will not readily absorb water. Examples of impervious surfaces include paved areas, roof tops, streets and sidewalks. Developed land cannot absorb the water as easily, if at all, and many flow patterns are changed. In order to control the storm water, a storm drainage network has been built. These facilities must be operated, maintained, renewed and replaced in order to provide a safe flow of storm water.

To control storm waters and receive the benefits of that control, there is a cost. Since everyone in the City benefits, The Denver City Council passed an ordinance in 1981 which authorizes a storm drainage service charge to be collected from the owners of all improved parcels of land.

How is my storm drainage bill calculated?

The storm drainage charge to a property owner is based on the relative impact the property will have on the storm drainage system. For instance, a parking lot will have more storm runoff than a grassy area of the same size. The charge is based on the ratio of impervious surface area to total parcel area. An impervious surface is a man-made area that will not readily absorb rain water as it falls. Based upon that ratio, a rate is applied to the impervious area to calculate the annual charge. The higher the ratio, the greater the rate. This calculation is applied in the same manner whether the property is residential, commercial or industrial. 

Calculate your Storm Drainage bill

How does Wastewater measure my total parcel and impervious area?

By using the parcel lines that Denver County Assessor has listed. We utilize a geospatial measuring software of all impervious surfaces and roofline-to-roofline of all buildings within the parcel boundaries. If there is any discrepancies or errors, an investigator can make an onsite visit to verify and/or provide a remeasurement of the impervious areas. 

If you believe your impervious area is incorrect, you can request a remeasure.

How many times a year do I get billed for my storm drainage fee?

Twice a year. Your bill consists of two six month cycles.

How does my storm drainage bill compare to other cities?

Denver’s storm and sanitary bill rates are currently about $100 lower than the average for other larger Colorado cities. With the rate changes that were approved in 2016, Denver would be about $60 below the average in 2017, when the first full year of the rate change takes effect.

How are my storm drainage charges different from the Mile High Flood District charges on my property tax statement?

The charges on your property tax statement are collected for the Mile High Flood District. MHFD is a regional agency, involved in the planning and funding of major storm drainage projects, many of which cross city and county boundaries. The MHFD charge is a tax and is based on the assessed value of your property.

By contrast, our storm drainage fee is not a tax. It is based on the relative impact the property will have on the Storm drainage system. Our charges are not a duplication of funds collected on behalf of MHFD.

For more information on MHFD, see mhfd.org

Why is my sanitary sewer bill combined with my water bill?

To reduce costs and as a convenience to customers, a combination bill was developed. The sanitary sewer bill is based on the water consumption metered by the Denver Water Department. This information is included on your combined bill.

How is my sanitary sewer bill calculated?

Each year, we establish a new winter consumption for every residential customer, based on the metered water consumption shown on the February bill. The winter consumption sets the sanitary sewer charges for the entire year, starting with the March bill. Even though your water use may increase during the summer, your sanitary sewer charges will remain constant until a new winter consumption is calculated.

The sanitary sewer charge for commercial property is based upon actual metered consumption in each billing period during the year.

How does my sanitary sewer bill compare to other cities?

Your sanitary sewer charges are actually lower than many other cities, both locally and nationally. A national 2009 survey shows that Denver's residential sanitary sewer rates are the 3rd lowest of 36 large U.S. cities surveyed.

Who do I contact when I have questions about my storm drainage or sanitary sewer bill?

You may phone Wastewater's Customer Service unit at (303) 446-3500.

Our telephone hours are 7:30 a.m. to 4:00 p.m., Monday - Friday. Our offices are open to answer your questions from 7:30 a.m. to 4:00 p.m., Monday - Friday. We are located at 2000 West Third Avenue, Denver.

What happens if I don't pay my bill?

You should pay any past due amounts as soon as you can. Wastewater Management Division does not charge a late fee. However, if you fail to pay either sanitary sewer or storm drainage charges, a service lien may be filed against your property. When a service lien is filed with the city’s Treasury Division, Treasury will increase the balance owed by a filing fee and monthly interest charges. All liens filed are to be paid directly to the Treasury Division. For a pay-off of a service lien contact Treasury at (720) 913-9500.

Service lien delinquencies unpaid as of November of each year are sold at a tax lien sale. The City Treasurer will then file a tax lien against the property. If the tax lien and interest is not settled within three years from the date the tax lien is filed, title to the property may be lost to a Treasurer's Deed.

Billing & Payment Questions

What are the steps for making an online payment?

  1. After typing in the link www.denvergov.org/stormpay (found on your Storm Drainage Service Charge invoice) into the address bar of your internet browser, the Pay Now window appears. There is an example of the Storm Drainage invoice showing the information you need to access your account.  Click Pay Now.
  2. Type in the Account Number and the Impervious area as previously shown in the example. Click Next.
  3. The current balance and account information are displayed.  If this information is correct, click Continue.  You may add additional accounts you wish to pay using the same credit card information by clicking on Add More.  You can return to the previous screen by clicking Back.  The Base Amount can be changed at this point.
  4. This account is now in the Shopping Cart and the amount to pay can be changed by clicking Edit.
  5. Proceed to complete the transaction by clicking Checkout Now.
  6. Complete the required fields: Payor Name, Phone, Credit Card information. If you wish to receive an e-Mailed copy of the receipt, enter in the e-Mail address. Once all information is entered, click Complete Transaction.
  7. You will see the receipt.  To print from this page, click Print Receipt . Your payment is now posted to your account.

Can I pay in person?

Yes, you can pay at the Webb building with CPD cashiers, who are temporarily located across from the Treasury department on the first floor. You will need your account number and impervious area.

Which credit cards are accepted?

The major credit and debit cards accepted are VISA, MasterCard, and Discover.

Is my credit card information secure?

The Wastewater Management Division of the City and Department of Transportation and Infrastructure does not store or retain credit card information and email addresses after payments are processed. To ensure a secure online payment, we provide 128-bit-SSL encryption.

Is there a fee for using the online bill payment service?


Is there any discount/low-income program for the storm drain or sewer bills?

No, there are no current programs available.

Is there a minimum amount I can pay?

No, there is no minimum amount.

Can I make a partial payment or pay in advance?

Yes, partial and advance payments are accepted.

What if I have late or overdue payments?

You should pay any past due amounts as soon as you can. Wastewater Management Division does not charge a late fee. If you fail to pay sanitary sewer or storm drainage charges a service lien can be filed against your property. When a service lien is filed the balance owed is increased by a filing fee and monthly delinquency interest is charged. Service lien delinquencies unpaid as of November of each year are sold at a tax lien sale. The City Treasurer will then file a tax lien against the property. If the tax lien and interest is not settled within three years from the date the tax lien is filed, title to the property may be lost to a Treasurer's Deed.

Can I set up my account for automatic payment for the yearly billing?

No. Automatic bill payment is not available.

Do I need to make an account online to pay?

No, you can pay without an account.

Will I get a receipt as proof of payment?

There are two ways to get a payment receipt:  (1) Enter an email address on the Payment Information screen to receive a receipt via email.  (2) Click on Print Receipt after the transaction is completed successfully.

What if I make a payment but don't receive an email confirmation?

Email confirmations are only generated if you enter an email address on the Payment Information screen.  The receipt will go to the email address that you provide in that field.  If you entered a correct email address and did not receive a receipt, contact Wastewater Management Division Customer Service at (303) 446-3500 or wmdcustomerservice@denvergov.org.

How do I request a refund?

Fill out this form, including proof of payment and proof of identity. The form will be emailed directly to our billing department to process your refund.

Click here to view form.

I am trying to pay online but it says account number xxxx-xx-xxx-xxx cannot be found please check your entry and try again. Error: Failed

During the periods when we are processing our liens, our online payment portal shuts down for everyone. Please wait for 5 business days to try to pay again whether that be online, or in person. If you still have an issue, then please call us at 303-446-3500.

How to request a status/transfer (for Title Companies only)

Wastewater billing department will provide the status/transfer for both Solid Waste and Storm Drainage billing. Please submit a status/transfer request using our online forms.