Move: WASD, Space jump, Shift run, mouse look. G god mode (noclip, wheel = speed), F fly, X x-ray to see the pipes underground, 1-5 pick block, left-click break, right-click place.
Weather: R rain, T storm (3x rain), N standard or leaky butt, E empty the butt onto the garden.
Rainwater system: roof → gutters → first-flush diverter and downpipe → water-butt. Leaves slowly clog the gutters (shown in the panel): right-click a gutter to clear it, otherwise less water reaches the butt. When the butt is full the overflow goes down the sewer to the treatment works. The green roof and solar panels are on top; use the stairs on the east side or god mode.
Inside the house (right-click): front door, toilets, shower and washing machine (rainwater, falling back to mains if the butt is low), basin and kitchen tap (mains from the water tower).
Treatment works (right-click): each tank to learn its stage; the screen rake, sludge pump, aeration blower, chlorine dosing unit and effluent sampler; the console in the office opens the control room. The river can be sampled too.
Storm Lab (L): design a storm (rainfall depth and duration), choose the catchment (roof) area, a green roof, the butt volume, the slow-drain hose (fitted or removed, outlet height and drain rate) or remove the butt altogether, and set the sewer capacity. Charts show the rainfall hyetograph, the outflow hydrograph and the water held in the butt, compared with no attenuation. Press Run to watch the storm in the world: clouds darken, the rain gauge fills, and if the sewer is overwhelmed the manhole on the lawn surcharges, pops its lid and floods.
Goal: use rainwater, keep the works inside its discharge permit through a storm (T), avoid storm-overflow spills and keep the river health bar and fish alive.