LDD-10 · Plumbing — Three Clusters
One-line intent
Three zones, tight stacks, short runs — everything falls cleanly to the east.Three independent clusters
North cluster
- Ground: large bath (Murphy zone), ILS bathrooms (shared wet wall)
- Upper: 2 north bedroom bathrooms
- Special case: ILS kitchen sink ~20' offset (route via floor or local drop)
Middle cluster (highest density)
- Ground: kitchen sink + dishwasher · WC · mech room
- Upper: laundry / ops core · 2 baths
- Primary service spine, tight integration with mech room
South cluster
- Ground: workshop WC + utility sink, equipment sink + floor drain
- Upper (LOW): bath/shower, optional kitchenette
Non-negotiable rules
- No cross-cluster fixture mixing
- No long horizontal routing between clusters
- Vertical stacking prioritized; toilets ≤ 6–8 ft from stack
- No plumbing in exposed ceilings · no soffits for plumbing
- East-side under-slab main drain → site sewer (east side of lot)
Open items / engineer review
- Hot water strategy — central tank? distributed tankless? heat-pump?
- Recirculation lines for ILS kitchen sink (else 60+ second wait)
- Drain venting strategy — through-roof in exposed-ceiling building
- Water softener / filtration (rural water = hardness)
- Backflow prevention
- Gas service stub-outs
Cost drivers
DWV $2–5K · Supply piping $22–43K · Fixtures (7 toilets, 10 sinks, 3+ showers) $25–45K · Hot water system $4–12K · Softener $2–6K. Total: $90–135K, budgeted $115K.Air-gap concerns
- ILS kitchen sink offset is the only weak point — document under-slab routing.
- Hot-water wait at ILS kitchen without recirc — daily friction.
- Slab penetrations vs radiant tubing — plumbing wins, radiant routes around. Coordinate.
- East main drain spans 120' — single drain failure disrupts whole building. Add cleanouts at each cluster.
- Vent stacks pierce roof — locate now to align with bays.
Cross-references
Diagram
Three clusters · east-side under-slab main drain · site sewer connection on east side of lot.