A California legislator once asked me “What’s the big deal? It’s only $1,000 (additional per house).” I responded with a then-recently released study – which has since been updated – showing how adding new costs to the price of a home kept hundreds of thousands of households from becoming homeowners. Alas, I knew that my answer would go nowhere, since the level of ignorance about marginal cost increases predominated among his colleagues in the Legislature.

Indeed, my response sailed right past him. He was just another member of the Capitol “club” – where the prevailing attitude was then as it remains today – “Home prices are so out of sight, what’s the harm of another $1,000?”

According to the economists at the National Association of Home Builders (NAHB) an increase of just $1,000 in the median new home price nationwide knocks roughly 120,000 U.S. would-be buyers out of the market. In California, where the median-priced home is over $500,000 – much higher than the country’s median home price – the impact is much less but still significant, depending on what income group you’re targeting.

(For your information, the same economists found that an increase of 25 basis points to the average mortgage rate would squeeze out even more – around 1 million home shoppers.)

To get that amount of displacement, NAHB used the median income necessary to qualify for today’s median-priced home (published by the Department of Housing and Urban Development (HUD)) in all states and selected metro areas and calculated a national rate of affordability (32.7 million) for a home priced at $355,183. On that basis, NAHB determined that for every $1,000 added to that price would disqualify 127,560 households from affording to buy the home.

In other words, NAHB found something many of us have been arguing with the Legislature, federal and state government agencies and localities for decades: increased costs – created by lawmakers or bureaucrats – make a difference. Nevertheless, these institutions have continued to legislate, regulate and administer policies with impunity: in such a way so as to chase as many as 10,000 or so California households back into apartments every year.

Take inclusionary zoning, for example. This is the local requirement that developers must set aside a certain percentage of houses or apartments – usually 20 percent – at “affordable” prices or rents for lower-income households. This set-aside is typically a condition of project approval. According to a landmark study – now almost 10 years old – the extra that an inclusionary-zoning requirement adds to a normal, market-priced home can in some high-cost markets run as much as $100,000. Think for a minute how many hopeful home shoppers or renters that one added cost displaces. Yet – even in the depths of the state’s housing crisis – inclusionary zoning is as popular as ever.

California already has high-cost housing, due to land prices alone. Inclusionary zoning simply adds a cost premium to the land you want to build on. For instance, the market price for a finished lot in “affordable” Riverside County will run you about $80,000. (That amount can easily be quadrupled if you plan to build closer to the coast.) Now, before assigning construction costs to the new home you want to build, add another $50,000 or more for inclusionary zoning – more than $100,000 in Orange County – to the land cost. Pretty soon – after building the house – you’re spending real money and you’ve already chased tens of thousands of homebuyers out of the market. That’s the reality.

Local costs – and there are many – aren’t the only excises government adds to the price or rent of a new house or apartment. Occasionally, the feds double down on regulatory costs – like those growing out of the Clean Water Act or the Endangered Species Act.

But, I started this discussion referring to the tariffs imposed at the state level of governance and the dismissive, sometimes arrogant attitudes at the Capitol and beyond. This year, like so many in the past, there are a number of bills in the Legislature which will add $1,000 or more per house. Many more passed last year and before. Take the solar-roof mandate, which takes effect in fewer two years from now and is at least worth in excess of $55,000 per home. That little extra is sure to send many shoppers packing.

Lawmakers and state officials just have to know that additional costs per home have real-life consequences – for tens of thousands of California families. There is authoritative evidence of this. Their attitudes need to change.