B 2.0
Retrofit on operating plants
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.
W/SS, Water and sewer Typical span 3–18 months
This is the scope the rest of the company exists to support, and the reason the self-perform number matters.
Nearly every municipal plant project in Colorado is a retrofit. Cities do not build new plants often; they expand, upgrade and replace the plants they have, usually because a permit limit tightened or the population grew. Which means the work happens inside a facility that has to keep operating, on a site that was laid out for a different plant, with drawings that may or may not match what is actually buried there.
The governing document on a retrofit is not the structural drawings. It is the sequence of construction: which basin comes out of service, what carries its load, for how long, and what the plant falls back to if something does not go as planned. That sequence is written and agreed before the work, and it is the thing an owner should interrogate hardest at bid time.
The hours that actually matter are the tie-ins. Everything else can be recovered from. A tie-in that goes wrong at two in the morning with a basin out of service is the scenario the whole plan exists to prevent.
Nothing is demolished until the bypass has been installed, started and proven under real flow — through a wet-weather event or an agreed equivalent test. That is a hold point on every retrofit we do, and it is not negotiable for schedule.
Define these before a proposal
- Current plant condition
- What is actually there, as opposed to what the record drawings say. On an older plant those are frequently different and the difference is expensive.
- Flow data
- Average, peak and peak wet-weather. A bypass sized on average flow is a bypass that fails during the storm it was bought for.
- Permit limits
- What the facility has to keep meeting throughout, and what the reporting obligation is if it does not.
- Acceptable outage
- What can be taken out of service, for how long, and in what season. This is usually the tightest constraint on the whole project.
- Operator involvement
- Who from the plant is present at shutdowns and tie-ins, and who has the authority to stop the work.
What you receive
Bypass plan, shutdown and tie-in procedures, as-built record
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 2.1 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 |
|---|---|---|---|
| 08.10 | Bypass pumping, 6–12 MGD Pumps, suction and discharge, redundancy, 24-hour attendance | DAY | $3,200–$9,400 |
| 08.11 | Bypass pumping, 1–6 MGD As above, smaller plant or a single process train | DAY | $1,400–$3,600 |
| 08.20 | Bypass mobilisation and setup Delivery, rigging, piping, testing before any demolition | LS | $28,000–$145,000 |
| 08.30 | Temporary process equipment Screening, pumping or dosing carried temporarily | MO | by scope |
| 09.10 | Shutdown and tie-in, planned Rehearsed, low-flow window, written procedure, contingency in place | EA | site visit |
| 09.20 | Selective structural demolition Inside an operating facility, with protection | CY | $95–$340 |
| 09.30 | Structure rehabilitation and coating Surface preparation, repair, protective coating | SF | $18–$52 |
| 09.40 | Confined-space entry, attended Wet wells, digesters, vaults, with rescue provision | DAY | $1,900–$4,200 |
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 2.2 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.
Can the plant really stay in compliance through construction?
On a well-planned project, yes — that is the entire point of the bypass and the sequence. What makes it fail is a bypass sized on average flow instead of peak wet-weather, a tie-in scheduled without a contingency, or a sequence that leaves the plant with no fallback for a period longer than a storm. All three are planning failures rather than construction failures, and all three are visible in the submitted sequence if somebody reads it properly at bid time.
What happens if the record drawings are wrong?
They frequently are, particularly on plants built in stages over decades. Where we find a condition that does not match the documents, work stops on that element, the owner and the engineer are told in writing the same day, and nothing is worked around until there is a decision. Improvising around an unexpected buried condition on a live plant is how a retrofit becomes a spill.
How are tie-ins scheduled?
At the lowest flow the system sees, which in most collection systems means the early hours of a weekday morning, and away from forecast wet weather. The procedure is written, the steps are walked through with the operators in advance, the materials are staged and checked, and there is a written point of no return with a contingency on either side of it. The plant's own staff are present and can stop the work.
Do you do emergency repairs?
This site makes no guaranteed-response claim, because none was supplied and a response time is a thing for a contract rather than a web page. Telephone and describe what has happened; we will tell you honestly what we can mobilise and when, and if somebody else can be there sooner we will say so.
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
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
Cast-in-place water-retaining concrete, vaults, tanks, headworks, grading, drainage and restoration — the civil scope that everything mechanical is bolted to.
- You receive
- Concrete test records, hydrostatic testing, record drawings
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