You either extend the public sewer to your frontage at your own cost, where the utility allows it, or use a septic system where the county approves one. Phoenix requires the developer to pay for a main extension and will not tap sewers 27 inches or larger. Maricopa County building permits need proof of one or the other.
Who decides which route you get?
The utility and the permitting agency, in that order. The sewer provider decides whether it will serve you and what an extension must look like. If there is no sewer provider willing to serve, the county's septic program becomes the path. Maricopa County says that for water and sewer availability you contact the Arizona Corporation Commission Utilities Division with your address or legal description, and that where no service exists, County Environmental Services handles septic system installation and permitting.
Maricopa County ties the two together at the building permit. For unincorporated areas, building permits for the primary use of a property must be accompanied by either a letter from Environmental Services that a septic permit has been applied for, or a letter from a sewage disposal system provider that it has agreed to provide service to the property. So the permit office wants a "yes" from one side or the other before it issues anything. See what a will-serve letter is for how that letter works.
What does extending the sewer involve?
Phoenix's code is the clearest published example. A developer who wants to connect a sewer main extension to a public sewer must submit construction plans and specifications to the Director, pay the established fees and charges, and get approved permits before construction. The city does not do the field engineering. The developer hires an Arizona-registered civil engineer and pays to design, permit and construct the extension, including the cost of acquiring rights-of-way and easements, the as-built plans and the city's inspection.
Two more rules from the same section matter when the main is far away:
- The city lays out the sewer. The Director sizes the main for peak flows and decides the layout of public sewer mains.
- Lift stations are yours. If gravity cannot carry the flow, the developer builds the public lift station at their own expense to the city's design standards.
Under Section 28-21(E), public sewer main extensions, lift stations and other appurtenances built under that article upstream of the tap connection become part of the public sewer when the City accepts them. That acceptance does not turn every private lateral into a public facility.
Section 28-23 offers a way to win some cost back through a repayment program. A Class 1 project is an off-site sewer main eight inches or larger that one developer builds and later developers connect to. A Class 2 project is a main 12 inches or larger, or a lift station with its force mains, that benefits a defined area and is likely to be connected to by other developers. Class 2 costs must exceed $1,000,000, unless the benefited area is solely State trust land and the Director waives that minimum. To qualify for a repayment agreement, the developer must submit at least three written sealed bids to the city before the city accepts the project, and the costs eligible for recovery include engineering, labor, materials and testing. For how the cost is split and how repayment can bring some of it back if later projects connect, read who pays to extend a water or sewer main.
Are there limits on where you can connect?
Yes. Phoenix's policy for service outside its city limits, Engineering Policy P-105 (adopted 2009), spells out what a sewer connection depends on. The property must front an operating sewer main, the system must have capacity for peak-hour flows, and the city's code and design standards must be met. Then it adds location rules:
- Big sewers are not tapped. Mains 27 inches and larger are interceptor sewers, not intended for tapping. For a main that size, the policy allows a connection only where an existing manhole sits within your frontage.
- Extensions depend on annexation in some areas. For unincorporated county areas outside another municipality's service area, main extensions are permitted only after the City Council approves annexation of a contiguous property. In some incorporated areas, sewer extensions are not permitted at all.
- Defined service areas differ. Where the city has established a sewer service area, extensions are permitted subject to requirements.
- Other jurisdictions need an agreement. Sewer service in jurisdictions not described requires an intergovernmental agreement.
The policy also says the applicant pays the outside-city development, impact, connection, repayment agreement and permit fees. Plans for a main extension also go to Maricopa County Environmental Services and the local municipality.
Septic is the other route. It is a real option in unincorporated areas where the county issues the permit, and it comes with its own approvals. P-105 shows how the two systems interact: when no sewer is available, the service application for the utility requires a copy of the approved septic permit from Maricopa County. Septic is often a stopgap. Scottsdale's sewer tap plan checklist, for example, has the plans show abandonment of onsite sewer systems (septic tanks) per County Health Department requirements when a property connects to the city sewer.
For a commercial project, the practical questions are how much wastewater the building will produce and whether the site can support a septic system at all. The county decides both, and the answer changes the site plan, so ask County Environmental Services early.
How do septic and sewer compare?
| Extend the sewer | Septic system | |
|---|---|---|
| Who approves | Sewer utility, then permits | County Environmental Services |
| Who pays | Developer, often including engineer, easements, lift station and inspection | Owner, including design and permit |
| Who owns it | City, after acceptance | Owner |
| Long-term | Utility charges apply; capacity fees by meter or fixture units | Pumping, inspection and eventual replacement |
| Risk | Cost of a long extension, annexation limits | Site suitability and use limits |
What should you do first?
- 1Get the sewer provider's written answer on service and on where the nearest usable main is and how large it is.
- 2Have an engineer measure the extension: length, depth, easements, whether a lift station is needed.
- 3Ask County Environmental Services what a septic approval would require for your use.
- 4If your extension would carry more flow than your site needs, ask the sewer provider whether a repayment program applies before you design it.
- 5Price both and decide before you buy or lease the site. The extension is often the item that changes a deal.
If your existing building sits on septic and a main has since been built nearby, see septic to sewer conversion in Phoenix and do you have to connect to city sewer. HQ Plumbing & Air handles the plumbing on your side of the property line, with a free estimate and the price up front. Rules differ by utility and county, so confirm the current requirements for your parcel.
For the related service-planning question, see what sets the meter size and capacity fee for a commercial building.