Homes under construction, however, are supervised by a different group: municipal building departments.
And if you thought the state inspectors were busy -- they average almost two inspections a day, in addition to testifying at hearings -- the city guys often have it much, much worse.
Inspectors for the city of Goodyear reportedly handle as many as 90 inspections daily. Phil Pettice, the Registrar's longtime chief of inspections, says he's heard that in Surprise, workers handle 45 inspections per day.
And that's a problem.
"You can't inspect 45 houses a day," Pettice says flatly. "When you do that, there are going to be things that slip through the cracks."
At that point, he says, inspectors only have time to check out those problems that pose an immediate risk to health and safety, like exposed wiring.
The right foundation, and the methods that drain water away from a house, will never top the list -- no matter how important they'll be, years down the road.
Inspectors say the frantic pace is a shame, because the guys who have the time to do it right can make a big difference.
Jack Holden, the building official in Marana, just north of Tucson, says his city got tired of seeing problems caused by improper grading, especially in areas with expansive soil.
Marana now requires builders to hire an engineer to certify that grading is correct on every house.
"If you look at the grade, you can't always tell," he says. "So we've asked them to prove to us that it works."
Holden says that his office learned from past mistakes. They now check the soil reports carefully, he says. They wait for the builder to show his grade certification. And they make sure gutters are on when gutters are needed.
But he knows not every city is so careful.
Even beyond the insane pace in some departments, newbie inspectors may not always realize how important having a good, dry foundation is, he says.
Holden chairs a professional association, Arizona Building Officials. The group now offers continuing education on foundation issues and drainage.
Still, he says, some inspectors may not realize the consequences: "A lot of times, building departments never hear about these things. The people complain to the Registrar, and we never hear about it."
It's not always the inspectors' fault, either. Builders tend to donate heavily to political candidates in the communities where they build; some inspectors may face pressure to greenlight a house, even when they have outstanding issues.
People connected to the building industry, too, tend to get involved in politics. Just look at Phoenix: Mayor Phil Gordon got his start as a developer. Former Mayor Skip Rimsza owns a big real estate firm. City council members Tom Simplot, Peggy Neely, and Doug Lingner all have real estate licenses.
And the Home Builders Association of Central Arizona channels money into politics at many levels -- not just the state. Mayor Gordon has accepted $1,000 campaign contributions. So has Maricopa County Supervisor Rose Wilcox. The home builders association even spent $25,000 to defeat an initiative in Mesa that would have required sprinklers in new buildings.
Politicians notice that kind of clout.
In a deposition for a construction defect case in Sun City Grand, subcontractor Jim Bebout claimed that builder Del Webb had ultimate power over cities like Surprise.
"I'm going to tell you that whenever there was a dispute, Webb went in and used a big hammer to get what they wanted out of municipalities," Bebout said, according to a copy of his deposition obtained by New Times.
(Del Webb has declined comment on Bebout's allegations, other than to note that he made the allegations only after Del Webb named him in a lawsuit.)
The only way a homeowner can make sure a builder has done due diligence?
Hire a private inspector, before moving in.
Scott Warga's company, National BuildMasters, frequently does home inspections for people with severe defects, people who've gotten desperate enough to hire a lawyer.
He's also central district director of the Arizona chapter of the American Society of Home Inspectors.
"Buyers need to have an independent, third-party inspection," Warga says. "There's nobody else looking out for them. The builder isn't. And city's doing minimal inspections, at best."
The average independent inspection costs just $300, he says.
"Nobody's building good homes," he says. "Builders are constructing homes to minimum standards -- and what they can get away with."