Seattle Bubble spreadsheets are updated even when content isn’t frequently posted. You can get access to the spreadsheets by becoming a member of Seattle Bubble.

If you’re wondering about the lack of posts on these pages recently, the explanation is pretty simple: There just isn’t much to say. The Seattle-area housing market has been in a protracted boom period with ridiculously low inventory of homes for sale and rapidly-climbing prices for years now. In a lot of ways it looks like the housing bubble that was in full swing when I started this blog in 2005, but what’s going on behind the scenes is very different this time around. Is it possible that Seattle really is special this time around and the “bubble” won’t burst this time? … Maybe?

Anyway, I’ve been meaning to update more of the charts of the “fundamentals,” so let’s start with an updated look at our affordability index charts for the counties around Puget Sound.

As of February, the affordability index is at the same level it was in July 2005, just three months before Seattle Bubble was launched.

Median home prices have already started to creep up, and interest rates are climbing, now at their highest levels since early 2014. The affordability index for King County currently sits at 88.1. An index level above 100 indicates that the monthly payment on a median-priced home costs less than 30% of the median household income.

I’ve marked where affordability would be if interest rates were at a slightly more sane level of 6 percent—73.0, which is worse than any point outside of the peak bubble years of 2006 and 2007.

If rates went up to a more historically “normal” level of 8 percent (the average rate through the ’90s), the affordability index would be at 59.6—six points below the record low level in July 2007.

Here’s a look at the index for Snohomish County and Pierce County since 2000:

The affordability index in Snohomish currently sits at 109.1, while Pierce County is at 121.2. Both down considerably over the last few years, and at their lowest points since late 2008.

You can calculate whether a home purchase scenario is “affordable” using the Affordability Index measure with my simple affordability calculator.

Tomorrow or Wednesday I will post updated versions of my charts of the “affordable” home price and income required to afford the median-priced home. Hit the jump for the affordability index methodology, as well as a bonus chart of the affordability index in the outlying Puget Sound counties.

As a reminder, the affordability index is based on three factors: median single-family home price as reported by the NWMLS, 30-year monthly mortgage rates as reported by the Federal Reserve, and estimated median household income as reported by the Washington State Office of Financial Management.

The historic standard for “affordable” housing is that monthly costs do not exceed 30% of one’s income. Therefore, the formula for the affordability index is as follows:

For a more detailed examination of what the affordability index is and what it isn’t, I invite you to read this 2009 post. Or, to calculate your the affordability of your own specific income and home price scenario, check out my Affordability Calculator.