Am I allowed to install a septic system inside city limits?

Sometimes. Being inside city limits does not by itself rule septic out; what usually decides it is whether public sewer is available. Some states require a property to connect to sewer when a line is close enough and the utility can legally serve it, or deny a septic permit in that case; rules vary by state, county and city. Oregon, as a worked example, requires denial of a septic permit when sewer is both physically and legally available (OAR 340-071-0160(4)(f)); for a new single home, sewer counts as physically available when the nearest connection point is within 300 feet (200 feet for a repair), and legally available when it can be reached by right-of-way or easement and local ordinance allows it (Oregon DEQ sewer availability form).¹ Florida takes it further for existing homes: once public sewer becomes available and the owner is notified, a working septic system must be connected within 365 days (Fla. Stat. 381.00655).² Cities can set their own rules too, so check with the city. “Sewer nearby” can also mean large costs for a main extension, connection fees or a private lift station; SiteFacts covers that in When “City Sewer Nearby” Means $100,000+. Your report asks whether the lot is connected to, or required to connect to, public sewer.

Citations

1. Oregon Department of Environmental Quality, OAR 340-071-0160(4)(f), official text published by the Oregon Secretary of State; Oregon DEQ, Onsite Wastewater Treatment (Septic) System Sewer Availability Form. ↩

2. Florida Statutes 381.00655, official text published by the Florida Senate; Charlotte County, Florida Utilities Department, FAQs: Gravity Sewer. ↩