If you live in a freestanding home on a nice size lot in Colorado, chances are good that you have single-family zoning.

That means that only one family lives in your house, and only one family lives in every other house in your single-family zone.

If you do have single-family zoning, the form and character of your neighborhood is going to be changed by Senate Bill 23-213, which is now being considered for adoption by the Legislature.

If SB 23-213 is enacted, the home next door to yours could be changed into apartments, with apartments being created inside the home next door and/or in a large, detached structure in the backyard.

Meanwhile, across the street from your single-family home, the property owner will have built a three-story-high six-unit apartment house with six different families living in it. The six or more automobiles driven by these six new families will be parked on the street in front of your single-family home, likely creating a parking problem.

There’s more. Over the back fence, they have just opened up another “cottage cluster.” That is four — or more — small, detached living units (no larger than 900 square feet) arranged around a common courtyard. SB 23-213 specifically forbids requiring the owner to provide off-street parking for all the extra automobiles coming into the neighborhood.

And, down the street from your single-family home, a nice set of townhomes (row houses) have just opened up for sale or rent on what was a single-family building lot.

SB 23-213 will allow all of these forms of multifamily housing in your single-family zoned neighborhood, and there will be nothing you and your neighbors can do to stop it.

As soon as SB 23-213 goes into effect, any property owner in a single-family zone in Colorado Springs will be allowed, as “a matter of right,” to install apartments in an existing house, build six-unit apartment houses in the backyard, and construct townhomes and cottage clusters.

To make such dramatic land-use changes under present law, a property owner would have to propose a zoning change and have it approved by their city planning commission and city council. Nearby residents opposed to the zoning changes could lobby and petition the planning commission and council to deny the changes at public meetings.

But no such avenues of appeal exist under SB 23-213. The Legislature will have granted the power to build multifamily dwellings in single-family zones throughout Colorado, and the cities of Denver and Colorado Springs will have to go along.

Living in a single-family zone governed by a legal homeowners association (HOA) will not protect you from this onslaught of state-required multifamily housing.

The new law mandates in-house apartments, backyard apartments, six-unit apartment houses, townhomes, and cottage clusters in all HOA-type associations. Your HOA board of directors, which normally decides on zoning issues in your neighborhood, will be powerless.

The same will be true for neighborhoods that are zoned as planned-unit developments (PUDs). There will be no way the current residents can stop property owners from installing state-permitted in-house apartments, backyard apartments, six-unit apartment houses, townhomes, and cottage clusters on their properties in the PUD.

The executive director of the state Department of Local Affairs, an appointee of the governor, will be in charge of seeing that SB 23-213, if enacted, is enforced throughout Colorado. It will be the executive director’s job to see that every property owner who wants to build higher-density multifamily housing in single-family zones, HOAs and PUDs gets to do so.

Many neighborhoods in Colorado have adopted master plans that provide for the future growth and development of the neighborhood. These master plans often involve zoning. SB 23-213 requires that all neighborhood master plans be reviewed and changed to conform to the state dictate for more multifamily housing in single-family zones.

Copies of all the revised neighborhood master plans must be sent to Denver for review to ensure compliance. One has to wonder: Do state administrators in Denver really have a better idea of what is needed in a neighborhood’s master plan than the people in Colorado who actually live in the neighborhood?

Supporters of SB 23-213 argue that Colorado’s cities need to be more densely populated. They point out that apartments are generally less expensive than single-family housing. Therefore, requiring multifamily zoning in all single-family zones in Colorado will help produce more affordable housing.

There are also climate-change benefits to SB 23-213. More people living in apartments in what are now single-family zones will encourage the use of mass transit, which will in turn reduce the use of automobiles and their damaging exhaust.

SB 23-213 will soon go to legislative committee hearings. If you question the wisdom of increasing multifamily land uses in single-family zoning in Colorado, you should contact your state senator and state representative and urge them to oppose this legislation.

Search the internet for “find my legislator Colorado” to get their names and email addresses, and give them your opinion about SB 23-213.

Tom Cronin and Bob Loevy are news columnists. Cronin has written extensively on state and local government. Loevy served on the Colorado Springs Planning Commission from 1972 to 1975.