A property manager sends the same shopping center out to three contractors and the high bid comes back several times the low one. Same buildings, same sidewalks, same dumpster corral, and nothing in any of the three explains the spread.
Here is the answer up front. A commercial pressure washing bid tells you nothing until every bidder prices the same written scope, against the same unit, with the same answers on insurance, wash water, hours and rework. Write that scope yourself and make all three re-price it. Most of the gap collapses, and what is left is a difference you can actually see.
I run crews here and I lose work to cheaper bids regularly. Read this as a contractor explaining how his own industry prices things.
The spread is scope, not skill
At the low end somebody is washing what he can reach in an afternoon with cold water and leaving. At the high end somebody may be recovering wash water, working before the stores open, and carrying a limit your legal review will not bounce. Both can be honest prices. Neither told you which job it was pricing.
Six things go missing from a commercial pressure washing quote in Charleston more than anything else:
The unit. A lump sum for "the property," or a price per square foot against a measured area.
The surface list. Sidewalks are not the dumpster pad, and the pad is not the drive lane, the awnings, the storefront glass or the service alley.
The standard. What clean means, and who decides.
Wash water. Contained and recovered, or pushed toward the nearest inlet.
The hours. Business hours are cheaper. They are also how you get tenant emails.
Rework. Whether a return visit is inside the price or a change order.
What a real scope of work spells out
If you have never written one, steal from a government buyer. The City of San Bruno, California put out a sidewalk pressure washing RFP in March 2025 that beats most private contracts I get handed.
It names exact street segments and which side of the sidewalk. Hot pressurized water, no chemicals allowed. It lists what comes off: dirt and stains, human and animal waste, food waste, gum, graffiti on sidewalks and trash cans. Then it carves out what must not come off, the Underground Service Alert utility markings, which is a line you only write after somebody blasted them away once.
It also makes every bidder list his equipment: make, model, year, PSI, noise decibel, crew size. Ask for that. A machine with a burner prices differently than one without, and on a grease-loaded pad it performs differently too, because heat does work that pressure alone does not.
Copy the pricing structure while you are at it. That RFP prices by unit per cleaning event and requires unit rates to include mobilization, debris removal and traffic control. One sentence, and it kills most change orders before they exist.
Say what "clean" means, and what happens when it is not
The best paragraph in that solicitation is the acceptance standard. The city inspects every location, notes unsatisfactory work, and gives the contractor two working days to fix it. Still wrong after that, and the city does the work itself or hires somebody else and deducts the cost from the contractor's payment.
You do not need that exact remedy. You need a remedy. Without one, "clean" is an argument between two people who both think they are right. Our version is a re-do guarantee: if it is not right, the crew comes back. Write it into the property manager pressure washing contract anyway, with a window and a named inspector.
The certificate of insurance is not the insurance
This is the most misread document in a bid packet, and the form warns you itself.
The current edition is ACORD 25 (2025/12), the version on the New York Department of Financial Services roster of approved certificates. Its header says the certificate is issued as a matter of information only and "confers no rights upon the certificate holder." It is a receipt, not coverage. Three parts of it get mixed up constantly.
Certificate holder is not additional insured. Certificate holder is its own box at the bottom. Additional insured status is recorded per policy line, in a column headed ADDL INSD. The form's own IMPORTANT notice says the policy must carry additional insured provisions or be endorsed, and that a statement on the certificate does not substitute for that endorsement. IRMI is blunter: certificates do not confer coverage or insured status. Ask for the endorsement.
The printed limit is not a guaranteed available limit. The coverages block warns that limits shown may have been reduced by paid claims, and a general aggregate is shared across the policy year. A $2,000,000 aggregate in January is not necessarily $2,000,000 in October.
Cancellation notice is not a promise to you. That box says only that notice will be delivered in accordance with the policy provisions. Not thirty days. Not any days.
I found no standard sizing a liability limit to a building's value, and anybody who quotes you one is making it up. What real buyers require is more useful: San Bruno wanted $2,000,000 general liability, $2,000,000 auto, $1,000,000 workers' compensation, plus endorsements naming the city. We carry $2,000,000 general liability, we send the COI before work starts, and where a property manager requires it the client can be named additional insured.
Workers' comp and the helper nobody put on a payroll
South Carolina does not require workers' compensation from every employer. Under S.C. Code Section 42-1-360(2), an employer regularly employing fewer than four people in the state is exempt. A two-man outfit can legally carry none, and the low bid is frequently a two-man outfit.
Now the helper falls at your property. What happens next is genuinely unsettled, and I am not your lawyer. Section 42-1-400 makes an owner liable for compensation to a subcontractor's worker where the work is "part of his trade, business or occupation." But in Keene v. CNA Holdings, LLC (2021), the South Carolina Supreme Court said the analysis starts with what the owner decided is part of its business, and that a manager who reasonably outsources work her workforce cannot handle has legitimately defined the business to exclude it. That cuts both ways. Statutory employer status can mean comp liability. No statutory employer status means no comp immunity either, and ordinary tort exposure instead.
An uninsured employer here also faces a daily penalty and loses the common-law defenses if the worker sues. Collect the comp certificate, keep it current, and ask your counsel and your carrier how they want this handled.
Wash water is a line item, not an assumption
Federal rules define an illicit discharge as any discharge into a municipal storm sewer not composed entirely of storm water, with narrow exceptions for firefighting and permitted discharges. That is 40 CFR 122.26. Wash water is not storm water.
Enforcement is local. That same rule makes municipal permit applicants enforce an ordinance preventing illicit discharges, which EPA's stormwater practices menu describes in detail. The inspector on your site is a city or county employee, not EPA. Every attempt I made to pull the Charleston ordinance text failed, so call your municipality's stormwater office instead of trusting my summary or your contractor's.
This is also where bid spreads come from. In that San Bruno contract the contractor covers storm drain inlets with 20-mesh or finer filter fabric, illicit discharge is flatly prohibited, and reclamation of all power wash water is priced as a separate alternate line. Water recovery is its own cost. Two contractors can quote the same square footage and only one has priced it.
The stormwater brochure attached to that contract says both the discharger and the property owner can be liable for pollutants reaching a storm drain, and that even biodegradable soap is harmful there. We use plant-safe surfactants and biodegradable detergents, so be clear on what that buys: it protects your landscaping if something gets away from us. It is not permission to send suds to an inlet. Containment does that, it costs money, and that is why it belongs on the bid as its own line.
Hours, noise, and the tenant who calls you
After-hours work is a normal contract term, not an upsell. San Bruno wrote the schedule into the document: the first week of each scheduled month, between 5:30am and 10:30am, Monday through Friday, with daily coordination with city staff.
Charleston has its own version of that math. A King Street storefront cannot be washed at 11:00am on a Saturday. A dumpster corral behind a restaurant has a window between the last dish and the first delivery truck. An office park in Northwoods can often be done midday if tenants get notice. Ask every bidder to price both, business hours and after hours, on one sheet. Then you are choosing instead of discovering.
Where we usually land, and what the gap buys
We are not the low bid. Sometimes we are the middle number. On a contract with after-hours work, water recovery and an additional insured endorsement we are frequently the top one. The gap buys a COI before work starts, additional insured status where your owner requires it, wash water handled instead of chased, and a scope tight enough to hold us to.
One honest limitation. Our re-do guarantee is a return visit, not a refund and not a credit. If something is wrong, the crew comes back and does it again. Some buyers would rather have money back than have a crew return, and if that is you, negotiate it before you sign.
If you run a portfolio instead of one building, the money is not in picking the best of three bids. It is in writing one scope you reuse across every site, which is most of what Property Management Exterior Cleaning work really is.
Take the quotes already on your desk, lay them against the six items above, and send back two questions: can I see the additional insured endorsement, and how is wash water handled and priced. If you would rather have one bid written that way from the start, request a quote or call 843-696-4739.
