B 5.0
Structures and site civil
Cast-in-place water-retaining concrete, vaults, tanks, headworks, grading, drainage and restoration — the civil scope that everything mechanical is bolted to.
W, Potable water Typical span 6 weeks–10 months
This is the scope that does not photograph well and decides whether everything else works.
A process structure is a concrete box that has to hold water, resist the ground, stay put through freeze-thaw for decades, and not leak. The mechanical equipment bolted into it is replaceable on a fifteen or twenty-year cycle; the concrete is not. Getting it right is permanent and getting it wrong is close to permanent too.
The things that actually go wrong are unglamorous and predictable. Shrinkage cracking from a placement sequence that ignored it. A construction joint detailed on the drawing and executed differently in the field. Backfill placed in lifts that were too thick, compacted to a number nobody tested, against a wall that was not braced for it. Each one is a decision made by a crew on a specific morning, which is one more reason to care who the crew works for.
The site civil around it — grading, drainage, access, restoration — is what the operators live with. A plant road that holds ice, a yard that ponds, a valve box buried under six inches of regrade: all small, all permanent, all avoidable.
Define these before a proposal
- Structure type and exposure
- Water-retaining or not, buried or exposed, and what freeze-thaw and chemical exposure it will see.
- Concrete requirements
- Mix design, permeability, crack-control reinforcing, joint detailing and curing regime.
- Groundwater and buoyancy
- Whether the structure needs dewatering to build and whether it floats before it is filled.
- Backfill and compaction
- Material, lift thickness, compaction criteria and the testing that proves it, plus bracing while it is placed.
- Restoration standard
- What the site has to look like at the end, to whose specification.
What you receive
Concrete test records, hydrostatic testing, record drawings
In the format the owner's records require, agreed at proposal stage rather than discovered at closeout. What happens at each stage is set out on the process page.
B 5.1 Pay items
What this scope costs, by the unit
Broken out the way an engineer's estimate breaks it out, so a district can assemble a realistic figure rather than guess at a lump sum. The full sheet is on the unit price page.
| Item | Description | Unit | Unit price |
|---|---|---|---|
| 05.20 | Cast-in-place water-retaining concrete Forming, reinforcing, placing, finishing, curing | CY | $1,450–$2,600 |
| 05.21 | Structural concrete, non-water-retaining Slabs, foundations, pads | CY | $820–$1,480 |
| 05.30 | Waterstop and joint sealant PVC waterstop, hydrophilic strip, sealant | LF | $46–$95 |
| 05.50 | Precast vault, set and sealed Delivered, set, sealed, with frame and cover | EA | $18,000–$72,000 |
| 05.60 | Protective coating, immersion service Surface preparation to standard, coating system, testing | SF | $22–$58 |
| 13.10 | Site grading and earthwork Cut, fill, moisture conditioning, compaction | CY | $14–$38 |
| 13.20 | Structural fill, placed and tested Imported, placed in lifts, density tested | CY | $42–$88 |
| 13.30 | Storm drainage Pipe, inlets, outfall, erosion protection | LF | $165–$390 |
| 13.40 | Plant road and hardstand Subgrade, base, asphalt or concrete | SY | $68–$155 |
| 13.50 | Erosion and sediment control Installed, maintained, removed | LS | $12,000–$68,000 |
Row bands are the APWA uniform colour code for what is in the pipe: W, Potable water potable water, SS, Sanitary sewer sanitary sewer, unbanded where a line covers both or neither. Units are LF linear foot, EA each, CY cubic yard, SY square yard, SF square foot, LS lump sum, MO month, DAY day.
Unit prices are USD planning ranges for the Colorado front range, exclude engineering, surveying, permitting, bonds, insurance, owner-furnished materials, easement and right-of-way costs and any applicable tax, and assume normal access and no undisclosed site conditions. They are published so a district can size a project before it spends money on design. They are planning ranges, not a bid. Reviewed October 2026. A price for your project comes from a bid or a proposal against a defined scope. See the disclaimer.
B 5.2 Questions
Questions about this scope
Specific to this scope. The general ones — bidding, bonding, insurance, weather days, pay applications, retainage — are on the FAQ page.
Why does the placement sequence matter so much on a water-retaining wall?
Because concrete shrinks as it cures, and a long wall placed in the wrong order restrains its own shrinkage and cracks. Placing in a planned sequence with the right joint spacing lets each section shrink before it is tied to the next. A crack in a structural wall is usually cosmetic; a crack in a water-retaining wall is a leak, and it is found at the hydrostatic test after the wall is finished and expensive to reach.
What happens if a structure fails its leakage test?
It gets repaired and retested, and that is the point of the test. Repairs range from crack injection to removing and replacing a section, depending on cause. What matters commercially is whose cost it is, and on our work a leak caused by our placement is our cost. That is worth confirming with any contractor before award, because it is not universal.
Do you do the earthwork and the restoration too?
Yes, and this is one of the places self-performance shows up as a real advantage rather than a claim. On a plant site the earthwork, the structure and the restoration interleave constantly; when they belong to three firms each one waits for the others. Our crews do the excavation, the concrete and the site work, so the sequence compresses to what the work needs.
How is compaction actually verified?
By independent density testing at a stated frequency, not by the crew's judgement. The testing firm is usually retained by the owner or the engineer, which is the right arrangement, and the results go into the closeout record. Backfill against a structure is the one place where poor compaction is invisible on the day and shows up as settlement years later, under something that is now hard to get at.
B 0.0 The other scopes
The rest of the schedule of work
New water and wastewater treatment structures and process systems, from excavation and cast-in-place concrete through mechanical installation, commissioning and operator training.
- You receive
- Commissioning and startup records, O&M manuals, operator training
Rebuilding a process train while the plant keeps meeting its permit. Bypass pumping, staged demolition, tie-ins scheduled at low flow, and a written procedure for every hour the plant is vulnerable.
- You receive
- Bypass plan, shutdown and tie-in procedures, as-built record
Gravity sewer, water mains and force mains in open cut and by trenchless methods, including the surface restoration that is what a resident actually sees when it is finished.
- You receive
- Pressure and leakage tests, CCTV inspection, record drawings
Wet wells, valve vaults, pumps, piping, electrical and controls, and the standby power that decides what happens to a collection system when the grid goes down.
- You receive
- Commissioning record, control narrative verification, O&M manuals
Send the drawings, or describe the problem
Telephone with what the facility has to do, what it does now, and the date it has to be finished. We will tell you what has to be defined before anyone can price it, what carries the flow while the work happens, and what the sequence would have to look like.
RN Civil Construction, LLC · 6025 S Quebec St, Englewood, CO 80111