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View Full Version : Roof drainage - to where?



Daryl May
03-29-2011, 03:27 PM
In a Florida townhouse, I found that three-out-of-four roof downspouts had been led to a sandy crawlspace under the house, and the water just dumped there. A subsequent homeowner solved the resulting "wetness" problem by connecting the downspouts to 3 in Sched 40 PVC pipe, leading to traps, and then to Y joints into the home's 5 inch(?) sewage system.

The problem looks to be solved now. Recent heavy rain has been handled without any evident problem. But I'm wondering whether this was legal for the year the home was built.

- - -

For reference: The foundations are block over concrete. The floor above is of pre-cast concrete beams. The home was built approx 1990.

Scott Patterson
03-29-2011, 04:09 PM
In a Florida townhouse, I found that three-out-of-four roof downspouts had been led to a sandy crawlspace under the house, and the water just dumped there. A subsequent homeowner solved the resulting "wetness" problem by connecting the downspouts to 3 in Sched 40 PVC pipe, leading to traps, and then to Y joints into the home's 5 inch(?) sewage system.

The problem looks to be solved now. Recent heavy rain has been handled without any evident problem. But I'm wondering whether this was legal for the year the home was built.

- - -

For reference: The foundations are block over concrete. The floor above is of pre-cast concrete beams. The home was built approx 1990.

Nope it is wrong....

Storm water or rainwater runoff needs to go into the storm sewer or out into the yard. By putting it into the sewage sewer you are increasing the load on the system by adding the additional water. Imagine if everyone did this and then imagine the problems that would happen at the waste water treatment plant.

Daryl May
03-29-2011, 04:54 PM
Thanks, Scott. I see the good sense behind separate stormwater and sanitary sewers. But faced with the situation at hand, I am wondering whether stormwater into the sanitary sewers was legal in Florida when the home was built approx 1990.

John Kogel
03-30-2011, 01:37 PM
Thanks, Scott. I see the good sense behind separate stormwater and sanitary sewers. But faced with the situation at hand, I am wondering whether stormwater into the sanitary sewers was legal in Florida when the home was built approx 1990.The point is that the work was not done in 1990. You say it was done recently. The present day rules apply. If you need confirmation, ask the local authorities. BTW, they will hit the roof if they find out someone has done that without consulting them.

Daryl May
03-30-2011, 03:51 PM
I didn't say the work was done recently.

I did recently venture into my crawlspace. I discovered what I reported. To at least verify that the previous wetness was not continuing, I went down there in a recent rainstorm and saw that all was dry.

So how to approach this? In my mind, a key point is whether the current plumbing was legal at the time the home was constructed. Does anybody know this? If not, can anyone tell me what section/subsection of the building code applies, and how I'd be able to access the old versions?

Sure, we'd all like old construction to be rebuilt to current code.

Scott Patterson
03-30-2011, 03:58 PM
I didn't say the work was done recently.

I did recently venture into my crawlspace. I discovered what I reported. To at least verify that the previous wetness was not continuing, I went down there in a recent rainstorm and saw that all was dry.

So how to approach this? In my mind, a key point is whether the current plumbing was legal at the time the home was constructed. Does anybody know this? If not, can anyone tell me what section/subsection of the building code applies, and how I'd be able to access the old versions?

Sure, we'd all like old construction to be rebuilt to current code.

Regardless of when it was done, if the city finds out that it is connected like this they will force you to change it. This type of stuff does not "grandfather-in" in most cases.

H.G. Watson, Sr.
03-31-2011, 02:06 PM
Apparently you've moved from your 150 ft. elevated balcony/condo in Tampa or you're discussing yet another (income?) property.

1. Hire a professional.
2. As before, contact your local office.
3. Plumbing is a health and safety issue - public health and public safety.
4. An engineer (you claimed elsewhere) should "know better".
5. Complete permit/plans history for the parcel at the local offices having jurisdiction (although the cagey layered description leads one to conclude you are the subsequent homeowner who performed the unpermitted modification to the home's plumbing systems).

Not really fond of your playing games. You clearly indicated that a "subsequent homeowner" made this creative "modification" to the roof downspout plumbing system and conjoined it to the home's sanitary sewer. This of course indicates something POST original construction. Since you began this topic with "I found that..." leading to "a subsequent homeowner.." did thus and so; and later revealed that this was your own property, and reverting back to the OP, your conclusion that the problem was solved.

The symptom may no longer be representing itself in the same negative fashion, but the "problem" is NOT "solved".

The resources remain the same. Contacting the local office with jurisdiction. That office will have the historical codes references along with local ammendments, and a designated repository for official reference copies of the designated codes.

Plumbing system design, connections, and materials required then and now, for reasons of public health and safety, compliance with the governing plumbing, public health, and safety codes.

From your failure to indicate slope, pitch, length, vents, and material for the "downspouts" as opposed to roof drains, I would say that on the general note, the "usual" downspouts are not generally approved as sanitary vents.

You also do not provide slope, pitch, size of the roof superstructure so one can calculate the volume (in DFU) using standard statistical data for the region including the rarer but required to be calculated "rainfall events". You also do not provide data on the home (so as to calculate DFU based upon standards, so as to determine if either/both 3" and 5" are adequate capacity. (likely not).

First things first, the treatment system; public or private, and how billed. First call - to the treatment facillity. Doubtful individual unit septic (doubtful "townhome" designation). If your "sewer" usage is billed based upon water meter "use" expect not. The utility/services entity likely has information publicly available regarding intentional or non-intentional ground water/storm water "infiltration" to the sanitary sewer system.

Contact your local office. Presuming it is still city limits of Tampa Florida, you can find that contact information linked in reponses provided in your October of last year thread "hijack" or "piggyback".

Note: Not all "townhomes" are really "townhomes" appearances can be deceiving. This can effect which codes or sections of the codes apply.

Clean Water Act and other local historical events (such as changes in the conveyance and treatment systems, especially after major catestrophic weather seasons, additional regional "cover" and "development", etc.) may also "play a role" in your historical research.

Expert historical research and application consultation with analysis expect between $125 and 250 per hour examination, documentation, research and report generation time. Expect higher rates for opinion analysis, depositions, and court appearances. Testing expect much higher expenses. If the sanitary system entity has found blockages (debris), back-ups, failures attributable to your creative "problem correction" expect "they" may hold you as the property owner, liable.

Remedial corrections/modifications to today's standards. Licensed, qualified contractors - permits and approvals, plans engineered/stamped by one qualifed to do so. Yes, upgrade and/or correction for the main may indeed be invoked.

H.G. Watson, Sr.
03-31-2011, 02:42 PM
<snip>...In my mind, a key point is whether the current plumbing was legal at the time the home was constructed. Does anybody know this? ... <snip>

Your mind's "key point" is in error.

Whether the modifications (extentions/expansions) to the sanitary plumbing system was legal and legally performed (permitted, plans submitted, qualified party performing correctly, and inspected and signed off by the authority having jurisdiction) at the time the modifications were made to the the roof drainage plumbing and the home's sanitary plumbing system is the key point.

You have already indicated this "creative" modication was made my a subsequent homeowner (suspect you), subsequently to the home's original construction and occupancy (previous owner).

Daryl May
03-31-2011, 03:05 PM
HGW et al, let me make it clear. I did not perform this modification. Under the home, I found some perforated drainage pipe that had obviously been the original construction. It was old (weeping stain marks from the perf holes) so it had been in use for a while before replacement ("subsequent" homeowner?).

The home must have gotten an Occupancy certificate with the drainage dumped into the crawlspace. I am not a construction or civil engineer, but that seemed like an inspection failure and a physical problem. I was hoping that the subsequent "fix" that i judged effective might be legal and conceivably even what the original approved plans and permit called for. It's clear, though, from your expertise and that of others that that is unlikely and perhaps irrelevant.

Checking into legality was why I wrote in in the first place. I will proceed as far as I can using your helpful route map, but probably avail myself of professional help before long.

Thank you all.

Stuart Brooks
03-31-2011, 07:33 PM
Regardless of when it was done, if the city finds out that it is connected like this they will force you to change it. This type of stuff does not "grandfather-in" in most cases.

Yep, strictly illegal here. Sewage charges based upon metered water use. It doesn't matter when it was done if it is disallowed or illegal now.