If you do it outside, try do it where the runoff won't contaminate something else. Drain it into a pit if necessary.
You can use a kiddie pool to contain the infected stuff and then pump or drain it to a pit.
You can get decontamination showers, with platforms and collection bladders, but you're getting into high dollar range again, and probably won't be able to survive the situation at that level, anyway.
Best is to have an enclosed decontamination entry into the house,
so you are out of sight, protected, and have the drain plumbed to a safe disposal field.
You can decontaminate, strip off the suit, hang it in a cabinet ready for it, along with the gloves, and boots.
Change into your other clothes if necessary, and then move into the house without fear of contaminating it.
I'd shop around extensively. The prices for the same things at different places can be very different.
Buy at least a couple extra of the lighter coveralls so you can practice getting in and out of them,
how much they weigh, how they restrict movement, and how hot you get in them.
Most can’t afford that level of deconatamination supplies, have the means for a decontamination room, a disposal area, or have the strict medical training for proper decontamination. Even the trained personnel in Africa have messed that last one up.
We have 50% hydrogen peroxide that we use for many things, and diluted for the decontamination of fresh produce, meats, cutting surfaces, etc. It is better than bleach. It is safe. If we do not have to ship it (local clients) it is $15 a gallon.
If you do not know us you can get concentrated H2O2 at swimming pool maintance stores, probably 27% or so. Hydrogen peroxide is your friend.
I watched this series about surviving disaster: pandemic. It shows you how to survive a biochemical attack and how to shelter in place after a contagion is loose.
http://www.spike.com/episodes/dxhbrm/surviving-disaster-pandemic-season-1-ep-109
I also bought the accompaning book for the series, and have just lent it to a neighbor who I want to keep prepared.
And for years, I also have in my side yard niche where I have a shelf for my pool equipment, a first aid kit and decontamination supplies, dishing washing soap, sponges, etc., a change of clothes in case we come home and have to clean off if we suspect we have been contaminated.