The legal issue for websites is whether website operators are operating “a place of public accommodation.” The statute lists 12 different types of public accommodations including somewhat of a catchall that includes “other sales or rental establishment.” The list, created when the law was passed in 1988, conceivably covers most commercial establishments, but does not expressly include websites.
Construction law is quite difficult, and takes experienced professional expertise. The Division of the State Architect functions as a building oversight agency on state-funded construction projects, and can only direct you to general resources at your local building department. If DSA is the jurisdictional authority, our "California Access Compliance Reference Manual" has all of the building code accessibility regulations and policies used on projects under DSA approval authority. The Manual is available as a free download as an Adobe Acrobat (PDF) file. The Manual is also available in hardcopy at technical bookstores throughout California.

The Department of Justice may file lawsuits in federal court to enforce the ADA Compliance, and courts may order compensatory damages and back pay to remedy discrimination if the Department prevails. Under title III, the Department of Justice may also obtain civil penalties of up to $55,000 for the first violation and $110,000 for any subsequent violation of ADA Compliance.
In this case, Barnett was a US Airways employee who injured his back, rendering him physically unable to perform his cargo-handling job. Invoking seniority, he transferred to a less-demanding mailroom job, but this position later became open to seniority-based bidding and was bid on by more senior employees. Barnett requested the accommodation of being allowed to stay on in the less-demanding mailroom job. US Airways denied his request, and he lost his job.
With this legislation, California joins state and municipal entities in other parts of the country that have similar web accessibility requirements for governmental entities and contractors.  This legislation fills a small part of a void the federal Department of Justice has decided for the time being not to fill, when it put its pending regulations that would set an accessibility standard for state and local (as well as private entity) websites on the inactive list.
What I suspect you are looking for is advice about how to make your home “accessible” for your aunt and uncle. The ADA and the accessibility requirements of the California Building Code are specifically for “facilities offering goods and services to the public.” As to making your home more accessible, an architect or a good contractor can help you. You can also find accessibility requirements in our digital guide to accessibility compliance in California (ADA4CA) which is available on iTunes, Amazon and Barnes & Nobel.
The lack of regulations here has led to the absolute worst-case scenario. People with disabilities have not been served since most companies are unaware this is an issue. Most don’t even realize this is something they have to consider until they receive a demand letter. That has certainly been the case for some of my clients. This leads to a scramble to get compliant. Unfortunately, it can take up to a year to do so depending on the complexity of the site. Meanwhile, plaintiffs’ attorneys across the country are taking advantage of the confusion. More than 260 website accessibility lawsuits were filed in 2016, and significantly more were filed by the end of 2017. But these numbers do not even begin to cover the cases that are settled pre-litigation.