The links provided are “engineered plans” prepared by engineers.
One more note. If it is new construction MAKE SURE YOU ASK FOR A SOIL ANALYSIS REPORT! All new construction is required to conduct a fairly expensive soils analysis. I simply asked the builder for a copy of the report that reflected the soil for my lot and he allowed me to photocopy it no problem. It turns out that the nature of my soil was only about 30 to 35% as likely to slide/move (soil viscosity) as the default assumptions used to make the generic standard plans put out by San Diego City/County. In short, my wall is overbuilt/engineered which is no problem with me. Gives extra peace of mind. Don’t listen to those that want you to get engineering for anything under 7ft. Just use the standard plans (WHICH WERE DRAFTED BY ENGINEERS). They make very conservative assumptions. Follow the plans to a “T” however. In my case the plans called for #2 rebar which is very thick and can’t be bent by manual rebar benders. The mason, consulting an engineering guide determined that a #3 and #4 rebar wired together provided 25% greater strength than a #2 by itself. The guide he referenced was the standard in the industry. When the inspecter saw this, even after agreeing with the 25% greater strength recommendation by the guide, refused to approve it because the plan said “#2 rebar” and advised that if we wanted to use the #3 and #4 tied together we would have to get our own engineering . . . DESPITE it being stronger and despite the inspecter acknowledging it was stronger. The mason then had to order custom bent #2 which he then wired to the #3 and #4 already in the footing. In short . . . I think my retaining wall footing could hold back Mt. Everest at this point. Lesson is . . . 1) use the standard plans they are free and are prepared by engineers, 2) get a soils report from the builder if you can, 3) make sure you follow the plans exactly. Best decision I made in my landscaping was to do the retaining walls. Practically doubled the size of my backyard.
One correction to my earlier post. The link was for retaining walls with “level backfill.” I think you are doing it into a slope which would be “sloping backfill.” The plans for that wall are here http://www.sandiego.gov/development-services/industry/pdf/infobulletin/ib222.pdf. Again it only goes to 6ft. My wall is 7ft but is governed by the county and not the city. I know when I built the wall in 2002 the standard plans allowed walls up to 7ft.
