Acid Wash Pricing Calculator: What to Charge to Acid Wash a Pool

Interior area. Footprint is length × width (round: π·r²). Wetted area adds the walls — perimeter × average depth — for the true plaster surface, which is roughly double the footprint. Average depth is (shallow + deep) ÷ 2. Oval and freeform pools apply a 0.85 bounding-box factor (an approximation, not a cited constant).

floor      = length × width            (round: π·(D/2)²)
avg_depth  = (shallow + deep) / 2
walls      = 2 × (length + width) × avg_depth   (round: π·D·avg_depth)
footprint  = floor
wetted     = floor + walls
refill_gal = footprint × avg_depth × 7.48        (when not entered)

billed_hours = max(labor_hours, 2)               2-hour minimum
labor_cost   = billed_hours × labor_rate
water_cost   = (refill_gal / 1000) × water_sewer_rate
base_cost    = labor_cost + acid + water_cost + supplies
subtotal     = base_cost × severity_mult         light 1.0 / mod 1.25 / heavy 1.5
price        = subtotal × (1 + markup_pct / 100)
implied/sqft = price / footprint                  always footprint, never wetted

The per-sq-ft cross-check always divides by footprint area (never wetted), so it stays consistent with the published $0.50–$0.75 per sq ft band — consolidated from HomeGnome ($0.60–$0.70), Homewyse ($0.56–$0.68), and FloridaDetail ($0.55–$0.67). A flag of "above" or "below" just means your own cost stack lands outside the national average — your real costs may justify it.

The job covered is the standard scope: drain → prep → apply diluted acid → rinse → refill. The 2-hour labor minimum and the $80/hr labor, $22 acid, and $114 supplies defaults come from HomeGnome's and Homewyse's decompositions; all are editable — regional spread is large (NYC ~$0.85 vs Dothan, AL ~$0.52 per sq ft), so no single rate is baked in.

An acid wash rarely travels alone on the invoice. When the waterline scale is the customer's real complaint, price that scope on its own with the pool tile cleaning pricing calculator instead of burying it in the wash. When the plaster stained because the water went green first, the green pool cleanup quote builder prices the drain-and-restore work that usually comes before the acid. And if draining the pool exposed a failing pump, filter or heater, keep that on its own line with the equipment replacement pricing calculator so the restoration quote and the hardware quote stay separable.