Can Drano Harm Pipes? YES.   In this article, we provide details of how Draino can damage the 3 most common sewer pipes materials.  In the last section, we’ll tell you how to determine which sewer pipes material your home has. 

Al’s Plumbing, in Plano, Texas Provides Full-Service Plumbing; Maintenance, Repairs, and Replacements For Every Plumbing Component In Your Home. We sell and install gas and electric water heaters.  Al’s is near your home in; Far-North Dallas, Murphy, Rowlette, and Wylie, Texas.  We service all homes in southern Collin County, TX, and northeastern Dallas County, TX with no additional travel charges.

Call Al’s Today To Discuss Any Concerns Or Problems You Have With Your Home’s Plumbing. 

We will arrange an appointment at your convenience. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

Can Drano Harm Sewer Pipes? YES.

This Article Provides Details On How & Why Chemical Drain Cleaners Can Damage 

The 3 Most Common Sewer Pipes Materials.

NOTE: Though We Mention Drano Brand.

This Information Applies To Any Brand Of Chemical Drain Cleaner.

Image Source: Embedded Link

Drain Max Gel Ultra Clog Remover’s Ingredients

  • 5% — 10% Sodium Hydroxide / Lye  (Highly Alkaline/ pH-14) — Is Very Corrosive.
  • 1% — 5%    Sodium Hypochlorite / Bleach. (Alkaline/ pH-11) — Is Corrosive.                                  NOTE: Household Bleach is not strong enough to be corrosive.
  • 5% — 10% Sodium Chloride / Salt.  pH-7 / Neutral-Is Not Corrosive.
  • Drano’s Corrosion-Inhibitor: Sodium Metasilicate Pentahydrate (Alkaline/pH-12.4). *6

Draino’s specific chemical identity and/or exact percentage/concentration is (legally) withheld as a Trade Secret.

The pH Scale Shows How Acidic (pH<7) OR Alkaline (pH>7) A Substance Is.  pH-7 is Neutral (neither Acidic nor Alkaline).

Highly Alkaline (High pH) is Corrosive.  // Highly Acidic (Low pH) is Corrosive. //  pH-7 is Not Corrosive.

Highly Alkaline (High pH) Corrosion Is Much More Destructive Than Highly Acidic (Low pH) Corrosion.

  • At pH<8.5 — corrosion (called: “acid attack”) can occur.  It causes rough pitted surfaces.
  • At pH>12.5 — corrosion (called: “caustic attack) can occur.  Caustic Gouging results in Rapid Corrosion.  Caustic Cracking causes metal to become brittle – resulting in cracks. *10

Image Source: Embedded Link

Drano Combines 3 Alkalines:

  • Lye (ph-14)
  • Bleach (pH-11)
  • Sodium Metasilicate Pentahydrate (pH-12.4)

Because Drano’s exact percentage/concentration of ingredients is  (legally) withheld as a Trade Secret — We can’t determine Drano’s exact pH.

3 Alkalines Can Cause Alkaline/Caustic Corrosion.  *10

At pH>12.5 — Corrosion (called: “caustic attack) Can Occur.

Drano Adds A Corrosion Inhibitor:

  • Sodium Metasilicate Pentahydrate Has Dissolvable Silica ** — which acts as a Corrosion Inhibitor.
  • It’s called: a Corrosion-Inhibitor because it reduces corrosion.   Preventing all corrosion would require a Corrosion-Preventer.
  • ** Dissolvable Silica is; Sodium/salt AND Silicate (glass that easily dissolves in water).
  • Sodium Sulphate or Sodium Nitrate is used to Prevent metal from becoming brittle. *11
  • Caustic Corrosion can not be prevented.  It’s reduced by ensuring excess High pH Akalies are not present.  *12


  • ***
  • *4
  • *5
  • *6
  • *7
  • *8
  • *9
  • *10
  • *11
  • *12

On A Side Note — Why Drano Bubbles

Image Source: YouTube Embedded Video Link

SHOWN: Drano Bubbling While Working On A Clog

Image Souce: YouTube Embedded Video

Two Reactions Chemical Drain Cleaners Create To Help Clear Clogs: Heat & Bubbling.  

A Common Misperception Is That Drano Boils While Working.  The Bubbling Is Actually Hydrogen Gas. How this gas is generated is described just below.

It’s Unlikely That Drano Reaches 212F degrees (temp at which water boils) while working.  Though Chemical Drain Cleaners Can Reach Temps Of (just) over 2oo F Degrees.

While Working, Drano May Exceed The Upper Temp Tolerance (140F Degrees).  We Could Not Find Any Documentation To Confirm Or Deny This.

This Is What Causes The Bubbling. 

  • Chemical Drain Cleaners Contain Bits Of Aluminum.
  • Their Bleach Reacts With The Aluminum Foil and Corrodes it.
  • Hydrogen Gas forms due to the corrosion of the aluminum bits.
  • The Hydrogen Gas Causes Draino To Bubble.
  • The bubbling helps to break up the clog.

Drano Combines 3 Alkalines With Water-Dissolvable Glass (as corrosion-inhibitor)

We’ve Presented The Facts About Drano’s 3 Corrosive Substances + 1 Corrosion-Inhibitor.  It’s likely that most (if not all) chemical drain cleaners include some sort of a corrosion-inhibitor.  Cast-Iron Sewer Pipes can last up to 100 years — yet this author has seen multiple 50-year-old homes owners replacing their Cait-Iron pipes.  Adding corrosive substances shortens Cast-Iron’s lifespan.     

If your home has Cast-Iron Sewer Pipes — You Must Decide if you’re willing to risk chemical drain cleaners’ corrosive effects on metal.  The likely costs to replace Cast-Iron (just below) should be factored into your decision. We present that information just below. 

A Costs Guide To Replace The Sewer Pipes Under A Home

Note: These Costs Don’t Include The Sewer Main Pipe — That Pipe Connects The House To The City’s Sewer Line.

  • $125.00 per linear foot of sewer pipe replacement.
  • Since most homes have plumbing along the outside edges.  Take the Width + Length Of A Home — for a guide to the Linear Feet Of Sewer Pipe.
  • A typical 2,000 Sq. Ft. single-level home is about 45′ deep X 45′ wide.  That’s 90 linear feet of sewer pipes — at $125.00 per foot = $11,250.
  • If Your Home Has A Slab Foundation: ADD +$3500.00 — to trench under the slab foundation (to gain access to the existing pipes). Slab Cost = $14,750.00
  • A slab foundation home costs the most.  The extra cost is for digging under the home.
  • A basement home would be the least expensive.  The home above on a basement = $11,250. 
  • A crawl-space home’s cost would be somewhere between.

NOTE:  This Cost Guide Is A Rough Estimate.  Actual Costs Are Affected By Many Additional Factors Such As;

  • Where you live.
  • The contractor you hire.
  • The time of year (especially for slab foundation) — because the ground is frozen hard in the northern 1/3 of the U.S. during winter.



3 Things Homeowners Can Do To Extend The Life Of Cast Iron Sewer Pipes

Note: These 3 Sewer Pipe Maintenance Methods Apply To All Sewer Pipes Materials. 

1. Never Use Chemical Drain Cleaners.  Their Chemicals Accelerate Corrosion Of Cast Iron. 

2. Never Put Fats, Oils, or Greases (FOG) Down The Drain.  FOG build-up Accelerates Corrosion Of Cast Iron. 

  • As FOG moves down the sewer pipes — it cools and sticks to the sewer pipe’s inner walls.
  • FOG has pH value <4  (as measured in a municipal sewer system’s grease catcher).
  • With pH<5 —corrosion occurs to Cast Iron Sewer Pipes. **
  • This Means FOG build-up accelerates corrosion inside Cast Iron Sewer Pipes.

TIP: Put Cooled FOG In A Resealable Container (like cottage cheese or glass jars with screw-on lids) — and put it in the trash.

This YouTube Video Shows FOG Build-Up Inside A Drain.

Image Source: YouTube Embedded Video Link

Shown: FOG Build-Up Inside A Drain

To View This Video — Click On The White Arrow In The Center Of The Image.

3. Perform Sewer Pipes Maintenance Every 3 Months — With An Enzyme Drain Maintainer 

PLUS  4. Ways To Unclog A; Toilet, Sink Drain, Bathtub Drain & Shower Drain Is Below This Section 

Enzymes Drains’ Maintainers Are Natural & Chemical-Free.  

The enzymes eat only organic waste.  Sewer pipes aren’t organic, so these products have NO effect on pipes.  The enzymes begin cleaning pipes from wherever they’re added to a drain.  They clean the entire surface (360 degrees) of the pipe.   Then, they continue further down the drain in search of more organic waste.

TIP: Add these products at the drain farthest from where your home’s sewer exits.

In basement homes, this exit point is easy to find.

In Slab & Crawl-Space homes:  If you have an alley, the home’s sewer exits at the rear of the home.

If no alley, the sewer exits from the front of the home.

Drano Max Build-Up Remover Is Their Enzyme Drain Maintainer 

TIP: Enzyme Drain Maintainers Are Safe For Food Disposers.  Chemical Drain Cleaners Can Damage Them.

Image Source: Amazon Embedded Link

Click On Image To: View Product, Read Details, or Purchase From

Note: This (liquid) Product’s Weight Requires Higher Shipping Costs Than RID-X Powder (shown just below).

As an Amazon Associate, Als earn from qualifying purchases.

Drano MAX Build-Up Remover Description:  “With a formula containing natural enzymes & bacteria, Drano® Max Build-Up Remover helps prevent clogs from forming in your pipes. NOTE: This is not a drain clog remover.  Use it on a monthly basis to keep drains running smoothly, and prevent clogs.

Though RID-X Is Marketed For Septic Tank Maintenance

It Works Very Well For Sewer Pipes Maintenance.   

TIP: For Drains — This Supply Lasts Notably Longer Than 2 Months (more product is used for Septic Tanks maintenance.)

Click On Image To; View Product, Read Details, or Purchase From

As an Amazon Associate,  Al’s earns from qualifying purchases.

(This Article’s Author Has Used RID-X Powder For Years.)

If You Prefer A Liquid Version

Image Source: Amazon Embedded Link

Click On Image To: View Product, Read Details, or Purchase From

Note: This (liquid) Product’s Weight Requires Higher Shipping Costs Than RID-X Powder.

As an Amazon Associate, Als’ earns from qualifying purchases.

This YouTube Video Below Shows Sewer-Sludge Build-Up Inside A Sewer Pipe.

Regular Sewer Pipes’ Maintenance With Enzymatic Drain Cleaners Minimizes Sewer-Sludge Buildup.

Image Source: YouTube Embedded Video Link

To View This Video — Click On The White Arrow In The Center Of The Image.

4. How To Unclog A; Toilet, Sink Drain, Bathtub Drain & Shower Drain 

Without Chemical Drain Cleaners

A Warning: 

  • If You Have Used A Chemical Drain Cleaner First — Don’t Attempt To Clear The Drain With Any Of These Methods.  
  • If a chemical drain cleaner doesn’t clear the clog — the standing water is now highly toxic.
  • You could splash yourself with the drain cleaner that’s in the standing water.
  • Call A Plumber, they know how to deal with chemical drain cleaners. 

This YouTube Video Shows How To Unclog A Toilet With A Plunger — NO Chemicals Needed

Image Source: YouTube Embedded Video Link

This YouTube Video Shows Clearing A Sink Drain In Under 2 Minutes With A Plunger — NO Chemicals Needed

Image Source: YouTube Embedded Video Link


This YouTube Video Shows How To Remove A HAIR CLOG From A Bathtub — NO Chemicals Needed

This Method Uses A Drain Snake (shown just below — it’s white)

Image Source: YouTube Embedded Video Link


This YouTube Video Shows How To Remove A HAIR CLOG From A Shower — NO Chemicals Needed

This Method Uses A Drain Snake (shown just below — it’s white).

Image Source: YouTube Embedded Video Link

The 3 Most Common Types Of Sewer Pipes


1970's built home

Nearly all homes built before 1975 Have Cast-Iron Sewer Pipes.

Most homes built during 1975-1980 have Cast-Iron Sewer Pipes.  Some Had ABS (black plastic) Sewer Pipe.

Most homes built After 1980 have PVC (white plastic) Sewer Pipes

photo of cast iron sewer pipe

Image Source: Dreamstime

Shown: New Cast Iron Sewer Pipe

photo of cast iron sewer pipe rusted all the way through the metal

Image Source: Shutterstock

Shown:  Cast Iron Sewer Pipes That Have Rusted All The Way Through.

Earlier in this article, we went into in-depth detail about how chemical drain cleaners accelerate the corrosion of Cast Iron sewer pipes. 

2 Ways To Restore Cast-Iron Pipes (versus replacement) 

A. Cured In Place Pipe Lining (CIPP)

NOTE: Al’s Does Not Offer Sewer Pipe Lining.

Pipe Lining (also known as: “Cured In Place Pipe Lining (CIPP)”.  Cost: $135.00 to $185.00 per foot.  Rehabilitates a damaged cast iron drain pipe by inserting a felt liner, soaked with a special epoxy — to create a pipe-within-a-pipe.

TIP:  If you have a basement or crawl-space, pipe liners are as expensive as replacing the pipe with new — go with a replacement.   If your home is on a slab, pipe liners eliminate the costs of digging under the home.   With any foundation — pipes liners can be done in hours.  It can take days to replace pipe (especially with a slab foundation).

This YouTube Video, Created By “This Old House” Demonstrates Adding Expoxy-Saturated Felt Liners To Cast Iron Sewer Pipes

Note: Al’s Does Not Offer CIPP Sewer Pipe Lining.

Image Source: YouTube Embedded Video

B. Spray On Epoxy Lining (no felt tube)

This YouTube Video Demonstrates Spraying An Expoxy Coating To A Cast Iron Sewer Pipe.

Note: Al’s Does Not Offer Spray-On Epoxy Sewer Pipe Lining.

Image Source: YouTube Embedded Video Link

ABS (black plastic) Sewer Pipes

abs sewer pipe

Image Source: Shutterstock

Most homes built during 1975-1980 have ABS Sewer Pipes.  

SHOWN: ABS (black plastic) Sewer Pipe Is Not Resistant To Strong Bleach Concentrations

Chemical Drain Cleaners Have The Following Ingredient:

  • Sodium Hypochlorite/BLEACH
  • Strong Bleach Concentrations may damage ABS (black plastic) sewer pipes. 
  • ABS degrades when exposed to high beach concentrations.

PVC (white plastic) Sewer Pipes

photo of PVC sewer pipe

Image Source: Shutterstock

Shown: PVC (white plastic) Sewer Pipe

PVC Sewer Pipe That Has Been Used Widespread Since 1980.

PVC Has Excellent Chemical Resistance.

PVC Has POOR Temperature Resistance

  • Sodium Hydroxide/Lye easily dissolves in water — and generates a great deal of heat. *1
  • Adding lye to water — can increase water temperature to up to 200 ° F. *2
  • PVC sewer pipe is rated up to 140° F.  PVC pipe performance ratings are computed at 73°F. 
  • PVC is a thermoplastic — and begins to degrade at over 140° F. *3
  • PVC becomes less stiff/rigid as temperature increases.


  • *1

Where You Can Identify Which Sewer Pipe Material Your Home Has

In The Central 1/3 & Northern 1/3 Of The U.S.

You can see the sewer pipe material at any Indoor Sewer Cleanout.  It’s in the basement OR In Slab or Crawl-Space homes — it’s in the utility room (where the furnace is).

Click Here To See An Indoor Sewer Cleanout: Indoor Sewer Cleanout

If The Link Doesn’t Work, Copy This Into Your Browser:

In The Southern 1/3 Of The U.S.

You Can See The Sewer Pipe Material At Any Outdoor Sewer Cleanout.

Click Here To See A (Cast-Iron) Outdoor Drain Clean Out: Outdoor Sewer Clean Out

Note: The Cast-Iron Pipe (In This Photo) has been painted white.  You can see gray metal where the paint is gone.

If Link Doesn’t Work, Copy This Into Your Browser:

q=southern+u.s.+outdoor+kitchen+sink+clean+out&tbm=isch&chips=q:southern+us+outdoor+kitchen+sink+clean+out,online_chips:sink+drain+cleanout+plug:vbozhVCExow%3D&hl=en&sa=X&ved=2ahUKEwjY9eSeyuT4AhXXQ80KHZRSCwMQ4lYoBnoECAEQKw&biw=1087&bih=554#imgrc=gO4joscHmo3_xMOutdoor Drain Clean Out In Exterior Wall  

The Injury Risks To You– While Using Chemical Drain Cleaners

Copy The Link Below Into Your Browser To See The “Safety Data Sheet” For Liquid Drano (highlights just below):


Drop An Open Bottle Of Chemical Drain Cleaner — And It’s Likely To Splash Onto Nearby Nearby Surfaces — Including You.

Drano’s Specifications Shown In Globally Harmonized System (GHS) Classification:

  • Hazard Classification // Hazard Category  // Hazards ID
  • Skin Corrosion // Category 1B // Causes severe skin burns.
  • Serious Eye Damage // Category 1 // Causes serious eye damage.

Composition Information On Ingredients\

  • Chemical Name // CAS-No. // Weight Percent
  • Sodium Hypochlorite-Lye // 7681-52-9 // 1- 5% (varies by product).
  • Sodium Chloride-Salt //  7647-14-5 // 1- 5%.
  • Sodium Hydroxide-Dissolved Chlorine Gas // 1310-73-2 // 1- 5% (varies by product).
  • Sodium Silicate-Rust Inhibitor // 1344-09-8 // 1- 5% (varies by product).
  • The specific chemical identity and/or exact concentration percentage of Drano are (legally) withheld as A Trade Secret.

The U.S. Dept. Of Heath & Human Services Website Say:

Warnings:May be corrosive to metals. Causes severe skin burns and eye damage.

Precautionary statements:

Call for medical advice if needed.  Have product container close by when calling.

Keep out of reach of children. Immediately call 911 if you suspect someone has ingested a chemical drain cleaner.  IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.

IF INHALED: Get fresh air and stay in a position comfortable for breathing.

IF ON SKIN (or hair): Remove product immediately.  Remove any contaminated clothing. Rinse skin with water/ shower.

IF IN EYES: Call 911.  Remove & discard contact lenses. Rinse cautiously with water for several minutes.


Can A Liquid Chemical Drain Cleaner Injur You?

  • Absolutely!  There is no disagreement about this.
  • Make a simple mistake while using chemical drain cleaners and you risk severe injury.
  • If you have used a chemical drain cleaner — don’t attempt to clear the drain with any other method.
  • If a chemical drain cleaner doesn’t clear the clog — the standing water is now highly toxic.
  • You could splash or expose yourself to drain cleaner in the standing water.


This article was about: “Can Drano Harm Pipes?” Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally, we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard), and Coleman HVAC (same company as York HVAC).

Al’s also provides full-service plumbing maintenance, repairs, and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s is near your home in Murphy, Wylie, and Rowlette.  We service all homes in southern Collin County with no additional travel charges.

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience and offer 24/7 Emergency Service.