Septic and water catchment advise

[Alpogi8]

I will be building an HPM package house 4b/3b in my lot at HPP. What is your advise regarding location of both structures. What's the regulation with regards to their distance from the house? Is it better if catchment is on a slab foundation? any advise is appreciated.

[kalakoa]

I can't find my notes from DOH so this isn't a complete answer.

Generally: structures above-ground must be outside the setbacks, which vary with lot size/zoning.

Distance from structure to water/septic tank is per County. Per DOH the septic tank can be in the setback because it's not an "above-ground structure".

Leach field is only 12x12 here.

Locate the water tank so as to mitigate damage if it ruptures, eg, downhill from the house.

[HereOnThePrimalEdge]

Locate the water tank so as to mitigate damage if it ruptures

Excellent advice.
I knew someone with a metal water tank near his home, the seams rusted, broke, and the resultant tank-tsunami washed through the house and blew out the electrical wiring. Probably a rare occurrence, but it can and did happen.

[kalakoa]

Related issue: servicability. If you ever need a water delivery or septic pump-out, it's best if the truck can drive right up to the tank, or at least have a clear space to drag the hose. I don't know how much hose they carry, might be worth asking around.

Foundation for catchment varies but is usually (?) sand. Large corrugated tanks work best when they have a concrete ring for the steel to rest on, this keeps the sand from leaking out around the edges. Slab would work best for a one-piece plastic tank, but that will require engineering and inspection. Sand isn't cheap, but it's still less expensive than concrete.

Water tanks (over 4' high?) require a permit, of course.

[leilanidude]

Look at where the neighbors houses are, including those behind your lot. Plan yours to get you as much buffer as possible, in ALL directions. Remember that most people will have all their windows open all the time. Do you really want to hear their conversations - or for them to hear yours?

[Alpogi8]

Thanks for the advise. We've decided to place our septic at the back of the house 30ft away on the right side and the catchment tank on the left side 30 ft away also in the back of the house. All within inside the 20 ft setbacks. catchment will also on concrete foundation.

[kalakoa]

All within inside the 20 ft setbacks.

Septic and leach field can be in the setback. This is especially important on very small lots.

Septic can be right up to the lot line, but a 5-foot setback is common.

If you're doing the site layout yourself: make sure the septic tank inlet lines up neatly with the lateral coming out of your house, because the pipe fittings only come in standard angles. There's no easy retrofit for an oddball alignment or angle.

3" lateral requires 1/4"-per-foot slope, at 4" you can get away with 1/8"-per-foot. Septic inlet will be 4".

Use long-sweep fittings, install cleanouts every 50'. The "two-way" style sold at Home Depot can be installed with a riser to the plug to match grade. ABS must be packed in #4 sand, not crushed rock. PVC is acceptable too, but then you're definitely shopping Central Supply because they have all the stuff.

(No, I'm not a contractor or inspector, this is just one of my hobbies.)