The City of Louisville's Sales and Use Tax rate is 3.775%. Sales tax is remitted directly to the City of Louisville, a Home Rule jurisdiction. The City is located in Boulder County.

Boulder County does not impose a general Use Tax, however the County does impose a Use Tax of 1.185% on motor vehicles and on construction/building materials. County Use Tax on motor vehicles is paid at the time of vehicle registration to the Motor Vehicle Division. County Use tax on construction/building materials is paid at the time of permit issuance for building and mechanical permits to the City (or to the county if for an unincorporated area).

Other City taxes filed separately from the sales/use tax return:

• City bag tax: $0.25 cents per bag
• Telephone Utility Tax: $8 per line per year
• Lodging Tax: The City has a lodging tax on lodging rentals of less than 30 days of an additional 3% on top of the sales tax imposition.

Frequency and Due Dates

Filing frequency is determined by the amount of sales tax collected monthly.

• $25 or less per year: Sales tax returns may be filed annually. Annual returns are due January 20.
• Under $100 per month: Sales tax returns may be filed quarterly.
• $100 or more per month: sales tax returns must be filed monthly. Monthly returns are due on the 20th day of the month following the reporting period.

Due dates:

• January–March: due April 20
• April–June: due July 20
• July–September: due October 20
• October–December: due January 20

Your mailed return's postmark date will confirm timely payment. For in-person returns, a city cashier will stamp the date upon receipt. Any due date that falls on a weekend or legal holiday will be extended to the following business day. Legal holidays include any recognized by the Federal government or the State of Colorado. 

Timely payment shall be evidenced by the postmark date if mailed; otherwise, timely payment shall be evidenced by the date on the receipt issued by the city cashier. Any due date which falls on a Saturday, Sunday or legal holiday recognized by either the Federal government or State of Colorado shall be extended to the first business day following such weekend or holiday.

Penalty of $15 or 10% of the tax due, whichever is greater for late filings.

1% interest of the tax due is added per month to the deficiency from the date due until the deficiency is paid.